The Lord commanded them to choose a lamb, a male without blemish.
This lamb was a type of Christ, so it must be perfect.
The Word of God is Life to those who find them and health to all their flesh. . . . . . Prov 4:22
God commanded Moses, "Get thee unto Pharaoh in the morning: lo, he goeth out unto the water; and thou shalt stand by the river's brink to meet him" Exodus 7:15
It's possible that Pharaoh went to the river in the mornings to offer his devotions to the God of the Nile.