They obeyed God by establishing a custom of consecrating the firstborn of man and animal to God. God said, “Dedicate to me all the firstborn sons of Israel and every firstborn male animal. They are mine.” (NLT, Exodus 13:1) The Israelites did not have to sacrifice their firstborn children. Instead, God gave them instructions to sacrifice animals. God told the Israelites to keep this observance every year, and tell their children the significance of it.