Question: When did Moses descend Mount Sinai with the 10 Commandments?
If the Exodus occurred in the month of Nisan (March/April), is it true that Moses came down Mt. Sinai during the Hebrew month of Tishrei (September/October)? Where is it written that he came down the mountain with the Tablets during Tishrei?
Answer: Dear Phillip,
Your two facts are correct! The Exodus did occur in Nissan, and yes, Moshe did descend the mountain in Tishrei.
Your confusion lies in a detail that may have slipped your mind: Moshe went up to Mt. Sinai twice to receive two different sets of the Tablets of the Ten Commandments!
Moshe first ascended Mt. Sinai for the original tablets on the 7th of Sivan, returning on the 17th of Tammuz (and thereafter destroying them).
He then went up Mt. Sinai a second time, on the 1st of Elul, and returned on the 10th of Tishrei --- Yom Kippur!
With Moshe's descent on Yom Kippur -- and by extension God's forgiveness for the sins that led to the destruction of the first Tablets -- the day was then set as a day for atonement and forgiveness forever more.
You can find this and more on the issue in Rashi's commentary to Exodus 32:1 and 33:11.
Rabbi Ari Enkin
Ramat Beit Shemesh, Israel
