Having spared the firstborn males of Israel (of man and livestock) in the final plague, on account of the blood of lambs painted on the doorposts, God instructed Moses to consecrate Israel’s firstborn males (including the livestock) to himself (Exodus 13:2). Once the Israelites would settle in the Promised Land, a firstborn male donkey could either be redeemed with a lamb or put to death by breaking its neck, but every firstborn son in Israel had to be redeemed (Exodus 13:13), presumably with five shekels (see Numbers 3:47).

God’s choice to take the Levites and their livestock as a substitute for the firstborn in Israel remarkably sets Israel free from having to pay that redemption price on their firstborn sons and animals.