Siman 417

The Rambam wrote at the beginning of the Laws of Sanctification of the New Moon: The months of the year are lunar months, as it is said: "the burnt offering of the month in its month." Thus far his words, meaning: the lunar month appears as something new, for in the first half it grows larger, and in the second half it grows smaller, until it is completely darkened, and afterwards it is renewed. This is not the case with solar months—no change is visible to the eye. And since the Torah said "in its month"—it is explicitly clear that the renewal must be visible, and this refers to lunar months. And it is said: "This month shall be for you the head of months"—so the sages said (Rosh Hashanah 20a): that the Holy One, Blessed be He, showed Moses the form of the moon and said to him: "When you see it like this, sanctify it."

And the years that we calculate with—they are solar years, as it is stated regarding Pesach: "the month of spring"; and regarding Shavuot it is written: "the festival of the harvest"; and regarding Sukkot it is written: "the festival of the gathering." And the growth of the crops, and their harvesting, and their gathering—is dependent only on the solar months, for the change of the seasons is dependent on the sun: the cold and the heat, the summer and the winter. And the solar year exceeds the lunar year by approximately eleven days. Therefore, when there accumulates from this surplus about thirty days or slightly less—one month is added to the year, and we make thirteen months in this year, and it has two months of Adar: "Adar Rishon," and "Adar Sheni." And this year is called "meuberet." And in nineteen years—there are seven intercalations, and this is called the "minor cycle."

And this is also the reason that sometimes they make Rosh Chodesh one day, and sometimes two days. Because the lunar month is twenty-nine days and a half, and seven hundred and ninety-three chalakim. And if so, it is necessary that one month be twenty-nine days, and one month thirty days, in order to balance the missing half day. And were it not for the seven hundred and ninety-three chalakim—there would always be one deficient month and one full month. But the surplus of the seven hundred and ninety-three chalakim accumulates over time into a complete day, and therefore we have Cheshvan and Kislev—sometimes full, sometimes deficient, sometimes one full and one deficient, in order to balance the calculations.

And one should not ask: Why do we need all of this exertion, whether regarding years or regarding months? Since the years follow the solar months—let us make every year eleven days longer than the lunar year, and we will not require the intercalation of years. And these eleven days of that month would belong to the previous year, and the remainder of the days of the month would belong to the coming year? And likewise regarding months: let us make every month twenty-nine days, a half, and seven hundred and ninety-three chalakim, and let us always make Rosh Chodesh one day. And the thirtieth day would be a half and seven hundred and ninety-three chalakim—belonging to the past month, and the remainder—belonging to the coming month.

However, the answer to this is as our sages, of blessed memory, expounded in Megillah (5a): From where do we know that we do not count days for years? As it is said: "for the months of the year" – you count months for years, and you do not count days for years. Consequently, if every year there are eleven days more than the lunar months, and in the coming month some of the days would belong to the past year and some to the coming year – behold, you would be counting days for years, and the Torah forbade this. Therefore, we wait until the days accumulate to a month, and we add a month, and we count the year by months. And they likewise expounded: From where do we know that we do not calculate hours for months? As it is said: "until a month of days" – you calculate days for months, and you do not calculate hours for months. Consequently, if every month were twenty-nine days and a half and 793 chalakim, and the thirtieth day would be – twelve hours and 793 chalakim for the past month, and twelve hours less 793 for the coming month – it would turn out that we count hours for months, and the Torah forbade this. Therefore, we wait another month, so that the hours accumulate to a full day, and we make Rosh Chodesh two days, and the month will be calculated by days. And from the words of the Rambam I learned all of this. And we learned in a Mishnah in Arachin (8b) that we do not have fewer than four intercalated months in a year, nor more than eight, see there. And also in the early days of the Prophets we find that they made Rosh Chodesh two days. (In I Samuel 20 it is written: "And it was on the morrow of the second month," which is the second day of Rosh Chodesh. And the Radak wrote likewise.)

It is a positive commandment from the Torah upon the great beit din, which is the Sanhedrin that was in Jerusalem during the time of the Temple, to sanctify months and years, and to calculate according to the wisdom of the constellations whether it is possible for the moon to be seen today or not, and to receive testimony of the month, as it is said: "This month shall be for you the head of months." And we have learned from the oral tradition, man from man until Moses our teacher, who received at Sinai from the mouth of the Almighty, that this is its explanation: This testimony shall be handed over to you, to Moses and to Aaron, and to everyone who stands after you in your place. And this commandment is not handed over to each and every individual like Shabbat, where each one counts six days and rests on the seventh day. Rather, Rosh Chodesh and Yamim Tovim are established by the great beit din. And they do not sanctify months or fix years except in the Land of Israel, as it is written: "For from Zion shall the Torah go forth..."

And all of this was during the time when there was still a Sanhedrin and ordained sages in the Land of Israel. But now, we rely on the calculations from the calendars of Hillel the Prince, the great-great-grandson of our holy teacher. When he saw the great dispersion of the Children of Israel, that we were scattered to the four corners of the earth, and the nullification of the Sanhedrin and ordination—he and his great beit din arose and calculated the months and the years according to the laws of the Torah and the wisdom of the constellations, and they sanctified the months until the end of the world. And in memory of this, we stand and bless the month: "Rosh Chodesh such-and-such is on such-and-such a day." And our primary reliance is on the calculation of Hillel the Prince and the ordained sages who were in his days. And they sanctified all the months and all the festivals, and they intercalated all the years fit to be intercalated, until the end of the world. And when the righteous redeemer comes—then we will again sanctify each month individually, as in days of old. And all of this the Rambam explained in his great book, and in the enumeration of the mitzvot, mitzvah 153. (And the Ramban there—his opinion is also thus. And he pilpeled there with the Rambam, and this is his conclusion, and also the intention of the Rambam is thus, as the author of Megillat Esther wrote there, see there. And be precise and you will find it easy.)

Therefore, our custom is: to stand at the time we bless the month, following the example of the sanctification of the month which was performed standing. And it seems that for this reason the custom is to know the molad at the time we bless the month. For when the beit din performed the sanctification—it is obvious that without knowledge of the molad they would not have sanctified. And as for why we practice this on the Shabbat preceding Rosh Chodesh—it is because there is a multitude of people, to inform everyone when Rosh Chodesh is. And a support for this I found in the Yerushalmi Sanhedrin (chapter five, halacha 3), on the Mishnah that one knew of the intercalation of the month, and one did not know. It says there, Rabbi Yose said: Such as I, who from my days never prayed Musaf, until I knew when the month was. And the explanation of the commentator is that it refers to the Musaf of Rosh Chodesh. And it is perplexing: for since he knows that he must pray Musaf—it is obvious that he knows that today is Rosh Chodesh. And there is one who explained that it refers to knowledge of the molad (Tziyun Yerushalayim). And it is perplexing: where is the molad mentioned here? Rather, it seems to me that it refers to the Musaf of Shabbat, according to our custom.

In Tishrei, it is not the custom to bless the month on the Shabbat preceding it. And the allusion to this is: "at the hidden time (bakiseh) for our festival day." Furthermore: how could we mention therein that "Rosh Chodesh Tishrei will be on such-and-such a day" and not mention Rosh Hashanah? And if we were to mention "Rosh Chodesh and Rosh Hashanah will be on such-and-such a day," it would be a change from every other Shabbat Mevarchim. Furthermore: this Rosh Chodesh is not called by the name "Rosh Chodesh" at all, but rather by the name "Rosh Hashanah." And in leap years, they say regarding the first Adar: "Rosh Chodesh Adar Rishon," and regarding the second: "Adar Sheni." And it is the custom to say: "He who performed miracles," and "May He renew it." And this is not a prayer on Shabbat, but rather for a good omen and the hope of redemption, for just as the month is renewed, so too shall Israel be renewed. However, regarding that which they say the "Yehi Ratzon" beforehand—I wonder how it is permitted to pray a new prayer on Shabbat, which is not in the formula of the blessings, but rather a prayer unto itself? And they request livelihood and other needs, and how is this permitted on Shabbat? And this prayer is the prayer of Rav throughout the year in Berakhot (16a). And its beginning is "that You grant us long life," and here they added at its beginning "that You renew for us this month for good and for blessing." And therefore it appears in the prayer books at its end "by the merit of the prayer of Rav." But this is a matter of ignorance: what relevance is there to "by the merit of the prayer of Rav"? And it appears that the printers erred in this, for the annotator noted that this is the prayer of Rav, and they did not know the intent, and they added the word "by the merit." But nevertheless, who permitted us to establish a new prayer on Shabbat? And if my strength were firm, I would abolish it. However, it is difficult to change the custom, and it requires great deliberation.

Rosh Chodesh is permitted for work. Regarding the women who are accustomed not to do work on Rosh Chodesh—it is stated in the Yerushalmi, the first chapter of Taanit, and in Pirkei De-Rabbi Eliezer (chapter 44) that it is a good custom, because they did not want to give their earrings to their husbands for the making of the Calf. Therefore, they were given an additional Yom Tov on Rosh Chodesh. And if there is a custom to do some types of work and not to do others—we follow the custom. This is specifically when it is known that the custom has been so from before. But in an unspecified case—women are forbidden from all work. And behold, among us, the wives of householders do not do work, but women who engage in a craft do work. And it must be said that they did not accept it upon themselves to lose their livelihood.

There are men of action who are accustomed to fast on Erev Rosh Chodesh, because of the waning of the moon. Great matters depend on this, regarding our situation. And in the future, the moon will be renewed like us, as we say in the blessing of Kiddush Levanah. Therefore, there are some among the Kabbalists who fasted until the molad. And among us, those who fast—fast until evening, and say "Yom Kippur Katan." And if there are ten—they read "Vayechal," and say "Aneinu," and as with every public fast. And when it falls on Shabbat or on Sunday—they fast on the preceding Thursday. And one who was accustomed to fast, and afterward is concerned for his health—requires hatarah. And if he is truly not in good health—he does not require hatarah, for it is forbidden for him to fast. And among us, they say the piyyutim and the confessions after Minchah, even though there are those who question this, and wrote that it is better to say them before Minchah (Magen Avraham). Nevertheless, the custom is not so.