This Month Shall Be Yours and the Sanctifying of the New Moon

"This month shall be for you" (Exodus 12:2). Rabbi Yitzchak said: the Torah ought to have begun only from "This month shall be for you," and why does it begin from "In the beginning"? Because of, "He has declared to His people the power of His works, in giving them the heritage of the nations" (Psalms 111:6). "This month shall be for you." Rabbah bar Shmuel taught: I might think that just as the year is intercalated when there is need, so the month is sanctified when there is need; the verse therefore teaches, "This month shall be for you" -- like this, see and sanctify. And this is like what Rabbi Yehoshua ben Levi taught: the witnesses are pressured concerning a month that was seen at its proper time, to intercalate it, but the witnesses are not pressured concerning a month that was not seen at its proper time, to sanctify it. Rabbi Shimon says: a father and his son and all relatives are valid for testimony about the new moon. And Rabbi Levi said: what is the reason? Because it is written, "This month shall be for you (lakhem)" -- this testimony shall be valid among you (bakhem); and the Rabbis say, this testimony shall be entrusted to you. If three saw it, and they are a court, two of them stand up and seat two of their colleagues beside the single one, and they testify before them, for the single one is not believed on his own account, and so on. Since we have learned that monetary cases require three, and if one is an expert for the public he may judge even alone, here too let him sanctify it alone -- this comes to teach us otherwise. And one might say, so indeed it is. There is no one more expert for the public in Israel than Moses, and yet the Merciful One said to him: not until Aaron is with you, as it is said, "And the LORD said to Moses and to Aaron, This month shall be for you." Is this to say that a witness may become a judge? But it was taught: a Sanhedrin that saw one person kill another -- Rabbi Akiva says, all of them are witnesses, and a witness does not become a judge. Rabbi Akiva said this only there, in capital cases, for the Merciful One said, "and the congregation shall judge, and the congregation shall deliver" (Numbers 35:24-25), and since they saw him kill a person, they can no longer see merit for him; but here, even Rabbi Akiva agrees.