Ibn Ezra on Ki Sisa 34:2

English: AND BE READY BY THE MORNING, AND COME UP. This is the third time, 11 That Moshe ascended Mount Sinai after God’s revelation. and each time Moshe stayed on the mountain for forty days and forty nights. 12 Moshe ascended the mountain after the revelation to receive the first set of tablets. He was then on the mountain for 40 days (Ex. 25:18). After Moshe broke the tablets he spent 40 days in prayer on behalf of Israel (Deut. 10:11). Moshe spent 40 days on the mountain when he received the second pair of tablets (v. 28). There are 120 days between the sixth of Sivan, when the revelation occurred,