Exodus 10:24-26

24Then Pharaoh summoned Moses and said, “Go, worship the Lord. Even your women and children may go with you; only leave your flocks and herds behind.”

25But Moses said, “You must allow us to have sacrifices and burnt offerings to present to the Lord our God.

26Our livestock too must go with us; not a hoof is to be left behind. We have to use some of them in worshiping the Lord our God, and until we get there we will not know what we are to use to worship the Lord.”