Exodus 10:24-26

24Then Pharaoh called Moses to come to him. He said, ‘Go and worship the Lord. Even your families may go with you. Only your animals must remain in Egypt.’

25But Moses said, ‘Then you will have to give us animals for our sacrifices and burnt offerings. We need our animals to offer to the Lord our God.

26So we must take our animals with us. Not one animal can remain behind. We must take them to worship the Lord our God. Until we arrive in the desert, we will not know which animals to use as sacrifices.’