Exodus 8:5

8:5 The Lord spoke to Moses, “Tell Aaron, ‘Extend your hand with your staff over the rivers, over the canals, and over the ponds, and bring the frogs up over the land of Egypt.’”

Exodus 13:9

13:9 It will be a sign for you on your hand and a memorial on your forehead, so that the law of the Lord may be in your mouth, for with a mighty hand the Lord brought you out of Egypt.

Exodus 27:21

27:21 In the tent of meeting outside the curtain that is before the testimony, Aaron and his sons are to arrange it from evening to morning before the Lord. This is to be a lasting ordinance among the Israelites for generations to come.