Saul was [forty] years old when he began to reign; and when he had reigned two years over Israel,
Referenced Verses
Exod 12:5 : 5 Your lamb shall be without blemish, a male a year old. You shall take it from the sheep, or from the goats:
Mic 6:6 : 6 How shall I come before Yahweh, and bow myself before the exalted God? Shall I come before him with burnt offerings, with calves a year old?