Exodus 13:15

13:15 When Pharaoh stubbornly refused to release us, the Lord killed all the firstborn in the land of Egypt, from the firstborn of people to the firstborn of animals. That is why I am sacrificing to the Lord the first male offspring of every womb, but all my firstborn sons I redeem.’

Exodus 20:10

20:10 but the seventh day is a Sabbath to the Lord your God; on it you shall not do any work, you, or your son, or your daughter, or your male servant, or your female servant, or your cattle, or the resident foreigner who is in your gates.