Exodus 12:43-51 - Institution Of The Passover
43 And the Lord said to Moses and Aaron, This is the law of the Passover: no man who is not an Israelite is to take of it: 44 But every man's servant, whom he has got for money, may take of it, when he has had circumcision. 45 A man from a strange country living among you, and a servant working for payment, may not take part in it. 46 It is to be taken in one house; not a bit of the flesh is to be taken out of the house, and no bone of it may be broken. 47 All Israel is to keep the feast. 48 And if a man from another country is living with you, and has a desire to keep the Passover to the Lord, let all the males of his family undergo circumcision, and then let him come near and keep it; for he will then be as one of your people; but no one without circumcision may keep it. 49 The law is the same for him who is an Israelite by birth and for the man from a strange country who is living with you.
50 So the children of Israel did as the Lord gave orders to Moses and Aaron. 51 And on that very day the Lord took the children of Israel out of the land of Egypt by their armies.