Shavuot as the Date of the Giving of the Torah

The sages taught: On the sixth [day] of the month [of Sivan], the Ten Commandments were given to the Israelites. R. Yosi says: On the seventh [day] of [the month]. Rava said: Everyone agrees [that the Israelites] came to the Sinai desert on the new moon, [as] it is written here: [In the third month after the children of Israel were gone forth out of the land of Egypt,] the same day came they into the wilderness of Sinai (Exodus 19:1), [without elaborating what day it was]. And it is written there: This month shall be to you the beginning of months; [it shall be the first month of the year to you] (Exodus 12:2). Just as there, [the term this is referring to the] new moon, so too, here [the term is referring to the] new moon. And [similarly,] everyone agrees that the Torah was given to the Israelites on Shabbat, [as] it is written here [in the Ten Commandments]: Remember the Shabbat day to keep it holy (Exodus 20:8), and it is written there: And Moses said to the people: Remember this day, [in which you came out from Egypt, out of the house of bondage, for by strength of hand the Lord brought you out from this place; there shall be no leaven eaten] (Exodus 13:3). Just as there, [the mitzvah of remembrance was commanded] on the very day [of the Exodus], so too, here [the mitzvah of remembrance was commanded] on the very day [of Shabbat]. Where [R. Yosi and the sages] disagree [is] with regard to the determination of the month, [meaning which day of the week was established as the new moon]. R. Yosi held: [The] new moon was established on the first day of the week, and on the first day of the week He did not say anything to them due to the weariness [caused by] the journey. On the second day of the week, He said to them: And you shall be to Me a kingdom of priests [and a holy nation; these are the words that you shall speak to the children of Israel] (Exodus 19:6).