John Lightfoot on Luke 4:2

[Forty days, &c.] Moses, in his dealings with God, fasted forty days three times, one after another. It was sufficient for Christ, having withal so great a conflict with the devil, to do it but once. Moses' first quadragesimal was Exodus 24:18: his second time was after he had destroyed the golden calf, Deuteronomy 10:10: the third was after the tables of the law had been made anew, Exodus 34:28. About that very time of the year wherein Moses ended his last forty days' fast, Christ began his; viz. about the middle of the month Tisri; and how long he continued it on in the month Marchesvan, it is not difficult to apprehend.