Since the Davidic dynasty evolved from Peretz who was likened to the moon, the Talmudic Sages [see Rosh HaShanah 25a], - when wishing to inform the Jews in other countries that the New Moon had appeared and been sanctified, would use the message 'David King of Israel lives and exists'[13]      

The Talmud, Sanhedrin 11b, indicates about Tehillim (Psalm) 81:3-4:

Tehillim (Psalm) 81:3 Blow the horn at the new moon, at the covering of the moon our feast day.

Now on which feast is the moon covered? We must say on the New Year (Rosh HaShana - Yom Teruah - Feast of Trumpets). And it is thereupon written:

Tehillim (Psalm) 81:4 For this is a statute for Israel, a judgment of the God of Jacob.

Just as judgment is executed by day, so also must the sanctification of the month take place by day.

The sight of the new moon which has reappeared is another occasion for celebrating this aspect of creation, and our awareness of it, by expressing gratitude for the renewal of life, and hopefulness for the future.

Rabbi Yohanan: Whoever blesses the new moon at the proper time is considered as having welcomed the presence of the Shekhinah.

Rosh Chodesh is also known as: Yom HaKippurim Katan. This means that Rosh Chodesh is a minor Yom HaKippurim. The devout will fast on the last day of the month and reflect upon his actions on the first day of the month.

CUSTOMS

"Originally, the New Moon was not fixed by astronomical calculations, but was solemnly proclaimed after witnesses had testified to the reappearance of the crescent of the moon. On the 30th of each month, the members of the High Court assembled in a courtyard in Jerusalem, named Beit Ya'azek, where they waited to receive the testimony of two reliable witnesses; they then sanctified the New Moon. If the moon's crescent was not seen on the 30th day, the New Moon was automatically celebrated on the 31st day."[14]

Entertaining the witnesses and taking their testimony, as well as the actual sanctification of the New Moon, all had to take place during daylight hours as this is a mishpat.

In addition to the witnesses, the molad for the new moon is also calculated by the Beit Din (Court) that has had their ordination conferred on them in a direct line from Moses. The Beit Din is the only body that is authorized by halachah to sanctify the new moon.

"But that it is not at all the planetary occurrence in the sky that fixes the beginning of the month, so that all that would be necessary would be for the law-officers to take note of such occurrence, is clearly evident from laws that refer to the case where on the 30th, while yet daytime, the new moon is visible and has been seen by the judges, the court, and by all Israel; or of the case where the thorough examination of the witnesses who come and testify that they have seen it, has been satisfactorily completed by day, but in either of these cases, if night has fallen before the judges have pronounced "it is consecrated", then the 30th ins not the first of the month, in spite of the fact that the new moon has actually been seen by everybody, or alternatively has been vouched for, and completely confirmed and established, the new moon only starts on the 31st. This is striking evidence that it is not the actual condition up above, but the consecrating declaration of the representatives of Israel that is the decisive factor on which the beginning of the month depends. This, the fact that the nation itself fixes the date of the beginning of the months is what the command refers to..."

"... It is not to be the conjunction of the moon with the sun; not the moon receiving the rays of illumination afresh, that is to induce the beginning of our months, it is not that, to which our celebration of the New Moon is to be dedicated. But each time the moon finds the sun again, each time it receives its rays of light afresh, God wants His people to find Him again and to be illuminated with fresh rays of His light, wherever and however, in running their course, they have had to pass through periods of darkness and obscurity. The moon finding itself again in conjunction with the sun is only a model for our finding ourselves again with G-d, the rejuvenation of the moon a picture of and an incentive to, our own rejuvenation. Moed is literally conjunction." Rabbi Samson Rafael Hirsch

Sanhedrin 42a.

In the school of Rabbi Ishmael it was taught: Had Israel merited no other privilege than greeting the presence of their heavenly Father once a month [by reciting the benediction over the new moon], they would be contented! Abbaye said: Therefore [since it is a greeting of God's presence], we must recite it standing.

It is the duty of God's people to recite:

Tehillim (Psalms) 118:24 This is the day HaShem has made; let us rejoice and be glad in it.

Women do not have to work on the day of the new moon.

OBSERVATION

A woman's cycle is the same as the moon's cycle. As a woman is renewed so too is the moon renewed. This intimate relationship is captured in the definition of “menses” from which menstruation is derived:

men·ses (mèn¹sêz) plural noun (used with a sing. or pl. verb)

The monthly flow of blood and cellular debris from the uterus that begins at puberty in women and the females of other primates. In women, menses ceases at menopause. Also called catamenia.

[Latin mênsês, pl. of mênsis, month.][15]

A month is, of course, related to the moon:

A unit of time corresponding approximately to one cycle of the moon's phases, or about 30 days or 4 weeks.[16]

So, it becomes obvious the there is a relationship between women and the moon. No wonder, then, that there is a custom for women to abstain from hard work on Rosh Chodesh.

Welcoming the Shechinah[17]

Since Kiddush Lavanah is considered to be an act of greeting the Shechinah, its blessing is distinguished from other blessings in the requirement that it be recited while standing, at a time of joy, while dressed in fine clothing, and in public – as if one were going out to greet a King.

The blessing for the new moon is generally recited on motza’et Shabbat, before the tenth day of the month, or on the first day that the new moon is visible, in fulfillment of the principle that the diligent fulfill mitzvot at the first possible opportunity. During the winter, it is not advisable to wait for motza’et Shabbat for fear of clouds.

In the month of Sivan, Kiddush Lavanah is recited on motza’et Shabbat so as to combine the blessing with the jow of the festival.

Even if one recites the blessing during the week, rather than on motza’et Shabbat, it is appropriate that he wear fine clothing in honor of this mtzvah and that he purify his spirit and his heart before the act of welcoming the Shechinah.

During the month of Av, because of the spirit of mourning that prevails, Kiddush Lavanah is not said before the ninth of the month. The custom is to recite it after the end of the fast on the ninth of Av, but to eat something first. Similarly, because of our preoccupation with the anguish of our sins before they are forgiven, during Tishri, Kiddush Lavanah is not recited before Yom HaKippurim. Rather, we wait until the end of the fast and recite Kiddush Lavanah when we leave the synagogue and prior to eating. Among Sephardic communities, the custom is to recite Kiddush Lavanah before Yom HaKippurim so that one may have an additional source of merit prior to his judgment.

In accord with the view of the Vilna Gaon, it is customary in many Jerusalem Synagogues not to wait for after Tisha B’Av or after Yom HaKippurim before reciting Kiddush Lavanah but to abide by the principle that the diligent fulfill mitzvot at the earliest opportunity.

Those who are especially careful in fulfilling the mitzvot make every effort to recite Kiddush Lavanah with a minyan, in fulfillment of the verse:

Mishlei (Proverbs) 14:28 The King’s glory is in the multitudes.

When reciting Kiddush Lavanah, one should not stand under a roof; nor should it be said while one is looking through a window or an open door. Rather one should go outside, as one would do were he greeting a king. However, if one finds it difficult to leave his home, the blessing may be recited inside, provided that the door or window through which he can see the moon is open and that there is nothing intervening between his eyes and the moon. If the glass of the window is clean and he can see through it clearly, one may recite the blessing without opening the window if he cannot open it because of the cold, etc.

Kiddush Lavanah is not recited before three full days and nights have passed from the time of the molad, the appearance of the new moon. Some authorities say, until seven full days and nights have passed. It may be recited until one half of the moon has passed; i.e., until the point that is halfway between the molad of that month and the molad of the coming month, since up to then the moon is in the process of renewal and achieving fullness. After half of the month has passed, the moon begins to diminish and Kiddush Lavanah may not be said.

Although Kiddush Lavanah is not recited on Shabbat, i.e. Friday night, or on festival nights, if it will be impossible to recite it on the next night, e.g. if Shabbat or the Festival is the last night of the month on which one can recite it, it may be said.

Women do not recite Kiddush Lavanah.

When reciting the blessing, one should first look up at the moon so as to see it at the time of the blessing, but should not look at it while reciting the entire service, for we pray not to the moon but to the He Who created it. When reciting the blessing, one should stand in a manner befitting the service.

Among some communities, it is customary to sing and dance after Kiddush Lavanah.

The new moon and Sabbath seem to be somehow linked. Notice the scriptures that use them together:

2 Melachim (Kings) 4:23 "Why go to him today?" he asked. "It's not the New Moon or the Sabbath." "It's all right," she said.

Yeshayah (Isaiah) 66:22-23 "As the new heavens and the new earth that I make will endure before me," declares HaShem, "so will your name and descendants endure. From one New Moon to another and from one Sabbath to another, all mankind will come and bow down before me," says HaShem.

Yehezekel (Ezekiel) 46:1 "'This is what the Sovereign LORD says: The gate of the inner court facing east is to be shut on the six working days, but on the Sabbath day and on the day of the New Moon it is to be opened.

Amos 8:5 Saying, "When will the New Moon be over that we may sell grain, and the Sabbath be ended that we may market wheat?"--skimping the measure, boosting the price and cheating with dishonest scales,

Colossians 2:16 Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day.

The Torah seems to place Rosh Chodesh on a par with the other festivals. In Numbers chapter 28, the musaf (additional) services for Rosh Chodesh are listed along with the other festivals. The order, in Numbers 28 and 29, is:

 morning (Shacharit)

 afternoon (Mincha)

 Sabbath

 Rosh Chodesh

 Pesach

 Hag ha-Matzah the first day

 Hag ha-Matzah the seventh day

 Hag ha-Bikkurim - Shavuot

 Yom Teruah

 Yom ha-Kippurim

 Succoth

The Rosh Chodesh sacrifices are identical in number and in kind with those of Pesach and Shavuot. In post temple times, a musaf service was established for Rosh Chodesh along with the other festivals. Rosh Chodesh was marked by many festive elements. There was a celebratory meal, and family gatherings were a natural for such occasions:

I Shmuel (Samuel) 20:18-29 Then Jonathan said to David: "Tomorrow is the New Moon festival. You will be missed, because your seat will be empty. The day after tomorrow, toward evening, go to the place where you hid when this trouble began, and wait by the stone Ezel. I will shoot three arrows to the side of it, as though I were shooting at a target. Then I will send a boy and say, 'Go, find the arrows.' If I say to him, 'Look, the arrows are on this side of you; bring them here,' then come, because, as surely as HaShem lives, you are safe; there is no danger. But if I say to the boy, 'Look, the arrows are beyond you,' then you must go, because HaShem has sent you away. And about the matter you and I discussed--remember, HaShem is witness between you and me forever." So David hid in the field, and when the New Moon festival came, the king sat down to eat. He sat in his customary place by the wall, opposite Jonathan, and Abner sat next to Saul, but David's place was empty. Saul said nothing that day, for he thought, "Something must have happened to David to make him ceremonially unclean--surely he is unclean." But the next day, the second day of the month, David's place was empty again. Then Saul said to his son Jonathan, "Why hasn't the son of Jesse come to the meal, either yesterday or today?" Jonathan answered, "David earnestly asked me for permission to go to Bethlehem. He said, 'Let me go, because our family is observing a sacrifice in the town and my brother has ordered me to be there. If I have found favor in your eyes, let me get away to see my brothers.' That is why he has not come to the king's table."

After the Beit Din had sanctified the new moon and uttered a blessing to God, special additional (Mussaf) offerings

Over the course of later history, by association, the day was considered especially appropriate for housewarmings, dedications, wearing new clothes, and saying Shehecheyanu over new fruit. It was also called the Day of Good Beginnings. The joyous spirit of the day, in biblical times, is suggested by two references:

Bamidbar (Numbers)10:10 Also at your times of rejoicing--your appointed feasts and New Moon festivals--you are to sound the trumpets over your burnt offerings and fellowship offerings, and they will be a memorial for you before your God. I am HaShem your God."

Hosea 2:11 I will stop all her celebrations: her yearly festivals, her New Moons, her Sabbath days--all her appointed feasts.

God does not specifically call Rosh Chodesh a rest day, but it is alluded to in:

Amos 8:4-7 Hear this, you who trample the needy and do away with the poor of the land Saying, "When will the New Moon be over that we may sell grain, and the Sabbath be ended that we may market wheat?"--skimping the measure, boosting the price and cheating with dishonest scales, Buying the poor with silver and the needy for a pair of sandals, selling even the sweepings with the wheat. HaShem has sworn by the Pride of Jacob: "I will never forget anything they have done.

The Talmud rules that work is permitted on Rosh Chodesh, but describes a tradition that women abstain from work on the day. [compare also Pirke de Rabbi Eliezer, chapter 45]

Rosh HaShana 23a Our Rabbis taught ‘Beacon fires are lit only for the new moon which has been seen at its proper time,[18] [to announce that] it has been sanctified. When are they lit? On the night following its announcement.[19] This means to say that we light beacons for defective months but not for full months. What is the reason? — R. Zera said: It is a precaution on account of a defective month which ends on Friday. [In that case] when do we light? On the termination of Sabbath; and if you were to insist that we should light up also for full months, this might give rise to confusion, since people would say: This month may be defective, and the reason why beacons were not lit yesterday is because it was impossible,[20] or perhaps it is full and they are lighting up at the proper time. But why should we not light up whether for a full month or a defective month, and when New Moon is on Friday not light up at all, so that since we do not light at the termination of Sabbath, in spite of the fact that we usually light for a full month, people will know that it is defective? — This nevertheless may lead to errors, since people will say, This month is full, and the reason why they have not lit up is because they have been prevented.[21] But why not light up for the full months and not at all for the defective months? — Abaye replied: So as not to deprive the public of two working days.[22]

Rosh Chodesh was celebrated only eleven times a year. In Tishri, Yom Teruah coincides with Rosh Chodesh; to this day, the new moon of Tishri is not proclaimed in advance in the synagogue; Yom Teruah rather than Rosh Chodesh is dominant liturgically.

It was an established rule that no year should consist of less than four nor more than eight FULL months.

Sanhedrin 10b THE INTERCALATION[23] OF THE MONTH BY THREE. [The Tanna of the Mishnah] mentions neither the ‘calculation’[24] nor the ‘sanctification’[25] , but the INTERCALATION of the month. [Why then the need of three for this?] Suppose it is not sanctified [on the thirtieth day] it will then be automatically intercalated! — Abaye therefore said: Read then, THE SANCTIFICATION OF THE MONTH. It is also taught to the same effect: The sanctification of the month and the intercalation of the year is to be determined by three. So R. Meir holds. But, asked Raba, does not the Mishnah say, the INTERCALATION? — Hence, said Raba, the Mishnah means that the sanctification made on INTERCALATION, that is on the intercalary day,[26] is determined by three; but on the day after it there is to be no sanctification. And this represents the opinion of R. Eliezer b. Zadok, as it has been taught: R. Eliezer b. Zadok says: If the new moon has not been visible in time, there is no need for the Sanctification next day, as it has already been sanctified in Heaven.[27]

The Hatzi (partial) Hallel, the yaaleh v'yavo prayer, and the musaf (extra) service are done.

In second Temple times, a ceremony "blessing the moon" (Birkat HaLavanah), sometimes called "sanctification of the moon" (Kiddush Lavanah), was developed. Recited from the third evening of the reappearance of the moon (when the moon is clearly visible) up until the fifteenth day of the month (as long as the moon is waxing), the prayer quickly became associated with the messianic hope.

The traditional service includes a candle lit to burn for twenty-four hours. Some use a floating light because it resembles the moon floating in the sky. As on the Sabbath or festivals, two challot (special egg bread) are served; they are round or crescent shaped, preferably, thus invoking the shape of the moon. A new fruit will be sought for the menu for the sake of making a Shehecheyanu. The egg soup, traditionally served at the seder, is often included as a symbol of life immersed in liquid. A quiche of circular shape, or a nut loaf, are popular choices for the menu. During the meal, zemirot such as verses from the Hallel or special Rosh Chodesh songs are sung.

Matityahu (Matthew) 24:26-31 "So if anyone tells you, 'There he is, out in the desert,' do not go out; or, 'Here he is, in the inner rooms,' do not believe it. For as lightning that comes from the east is visible even in the west, so will be the coming of the Son of Man. Wherever there is a carcass, there the vultures will gather. "Immediately after the distress of those days 'the sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the heavenly bodies will be shaken.' "At that time the sign of the Son of Man will appear in the sky, and all the nations of the earth will mourn. They will see the Son of Man coming on the clouds of the sky, with power and great glory. And he will send his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of the heavens to the other.

At Yom Teruah we also have a Rosh Chodesh. The moon will be in the west! Will the moon reflect the Shekhinah of the Son of Man when He returns?

Malachi 4:1-2 "Surely the day is coming; it will burn like a furnace. All the arrogant and every evildoer will be stubble, and that day that is coming will set them on fire," says HaShem Almighty. "Not a root or a branch will be left to them. But for you who revere my name, the sun of righteousness will rise with healing in its wings. And you will go out and leap like calves released from the stall.

Definition of Rosh Chodesh:

Rosh Chodesh literally means, "beginning renewal" and idiomatically means the "beginning of the month" or "new moon".

7218 ro'sh, roshe; from an unused root appar. mean. to shake; the head (as most easily shaken), whether lit. or fig. (in many applications, of place, time, rank, etc.):-band, beginning, captain, chapiter, chief (- est place, man, things), company, end, X every [man], excellent, first, forefront, ([be-]) head, height, (on) high (-est part, [priest]), X lead, X poor, principal, ruler, sum, top.

2320 chodesh, kho'-desh; from 2318; the new moon; by impl. a month:-month (- ly), new moon.

------------------- Dictionary Trace ------------------

2318 chadash, khaw-dash'; a prim. root; to be new; caus. to rebuild:-renew, repair.

Devarim (Deuteronomy) 4:5-6 See, I have taught you decrees and laws as HaShem my God commanded me, so that you may follow them in the land you are entering to take possession of it. Observe them carefully, for this will show your wisdom and understanding to the nations, who will hear about all these decrees and say, "Surely this great nation is a wise and understanding people."

"You shall guard and you shall do..." Rabbi Shmuel bar Nahman said in the name of Rebbe Yonatan, from where do we know that it is a mitzvah for each man to calculate the seasons and the months? It is written, "You shall guard and you shall do, for it is evidence, in the eyes of the nations, of the wisdom and understanding that has been given to you."

What is the wisdom and understanding that Israel possesses "in the eyes of the nations"? We must say that it refers to the calculation of the seasons and months. Concerning one who knows how to calculate and does not do so, the verse says, "They did not contemplate God's deeds, and they have not paid attention to the work of His hands." (Yeshaya 5:12)

New Moon Calculations

According to the Oral Torah

1. The beginning of the lunar month occurs at the moment of conjunction between the sun and the moon; i.e. at the moment when the position of the moon is exactly between the earth and the sun. At this point, termed as the molad, or "birth", the moon is not visible from the earth. At least six hours must pass before a very small portion of the moon will reappear. The day on which this occurs is regarded as the first day of the new month. (Rashi)

Rosh HaShana 20b — The latter statement would be seen to be false,[28] the former statement is not seen to be false.[29]