Exodus 34:18-20

Amplified Bible

¹⁸ “You shall observe the Feast of Unleavened Bread (Passover). For seven days you shall eat unleavened bread, as I have commanded you, at the appointed time in the month of Abib; for in the month of Abib you came out of Egypt.

¹⁹ “All the firstborn males among your livestock belong to Me, whether cattle or sheep. ²⁰ You shall redeem the firstborn of a donkey with a lamb; but if you do not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. None of you are to appear before Me empty-handed.