Exodus 7:7

And Moses was fourscore years old, and Aaron fourscore and three years old, when they spake unto Pharaoh.

Moses was fourscore years old ... The advanced age of the brothers was a pledge that they had not been readily betrayed into a rash or hazardous enterprise, and a proof, at the same time, that, under its attendant infirmities, they could not have carried through the work on which they were entering, had they not been supported by a divine hand.