Bo - Is Time Ours?

the ministering angels said before the Holy One blessed be He: ‘Master of the universe, when are You going to set the festivals, as it is written: “The matter came about by the decree of the messengers,”’ (Daniel 4:14). He said to them: ‘I and you will ratify what Israel decides and [how they] intercalate the year, as it is stated: “I call to God Most High, to God who completes for me” (Psalms 57:3), and so it says: “These are the festivals of the Lord [that you shall proclaim them] holy convocations…”’ (Leviticus 23:37). You [shall proclaim them], whether at the proper time or not at the proper time; I have no festivals other than these.

The Holy One blessed be He said to Israel: ‘In the past, it was in My hands, as it is stated: “He made the moon for the festivals…” (Psalms 104:19), but from here onward, it is given into your hands and is your prerogative; if you say yes, yes, if you say no, no. In any case, “this month shall be for you.” Moreover, if you seek to intercalate the year I will confirm it for you.’ That is why it is written: “This month shall be for you.”

Why did the Holy One blessed be He say this to Moses and Aaron? It is because sanctification of the month is [done] with three. When the Holy One blessed be He sought to sanctify the month, the Holy One blessed be He said to Moses and Aaron: I and [the two of] you will sanctify the month. That is what is written: “The Lord spoke to Moses and to Aaron.”

One who sees the new moon, what blessing must he recite?

... and some of them say "blessed who sanctifies Israel [and the months]" for if the people of Israel do not sanctify the new month, then the sanctified is nothing.

And do not wonder about this because Hashem sanctified Israel, as it says "You shall be holy for Me, for I Hashem am holy." and because [the people of Israel] are sanctified for Heaven, therefore, what they sanctify is sanctified.

From now on these months will be yours, to do with as you like, but in the years when you were enslaved when you had no control over your time, you had to work for others and do their will. Therefore, this will be the beginning of months, because this is the beginning of the reality for you to choose.

(9) Rabban Gamliel sent a message to him: I decree against you that you must appear before me with your staff and with your money on the day on which Yom Kippur occurs according to your calculation; Rabbi Akiva went and found Rabbi Yehoshua distressed, Rabbi Akiva said to Rabbi Yehoshua: I can learn from a verse that everything that Rabban Gamliel did in sanctifying the month is done, i.e., it is valid. As it is stated: “These are the appointed seasons of the Lord, sacred convocations, which you shall proclaim in their season”. This verse indicates that whether you have proclaimed them at their proper time or whether you have declared them not at their proper time, I have only these Festivals as established by the representatives of the Jewish people... he took his staff and his money in his hand, and went to Yavne to Rabban Gamliel on the day on which Yom Kippur occurred according to his own calculation. Upon seeing him, Rabban Gamliel stood up and kissed him on his head. He said to him: Come in peace, my teacher and my student. You are my teacher in wisdom, and you are my student, as you accepted my statement.

It is taught in a baraita: Who is an imbecile?

This is one who destroys whatever is given to him.