Parashas Eikev · Passuk 9:9
I had ascended the mountain to receive the tablets of stone, the Tablets of the Covenant that GOD had made with you, and I stayed on the mountain forty days and forty nights, eating no bread and drinking no water.
Torah Temimah points to Megillah 21b.
TT lemma: ואשב בהר.
English: “I sat on the mountain.” Above it says, “And I stood on the mountain.” Rav said: He stood while learning and sat while reviewing. R’ Chanina said: He was bent over. R’ Yochanan said: “Sitting” means lingering, as it says, “You stayed at Kadesh many days.” Rava said: Easy matters were learned standing, and difficult matters sitting.
Dispute (how Moshe “sat” / “stood” on the mountain)
The dual language of sitting and standing on the mountain is resolved as modes of study, or as delay, or as posture.