"When the LORD brings you into the land of the Canaanites and gives it to you as promised to you and your ancestors,
References for Exodus 13:11
you should set aside for the LORD whatever comes out of the womb first. All of the first males born to your animal belong to the LORD.
But every first male donkey you should ransom with a sheep. If you don't ransom it, you must break its neck. You should ransom every oldest male among your children.
When in the future your child asks you, ‘What does this mean?' you should answer, ‘The LORD brought us with great power out of Egypt, out of the place we were slaves.
When Pharaoh refused to let us go, the LORD killed all the oldest offspring in the land of Egypt, from the oldest sons to the oldest male animals. That is why I offer to the LORD as a sacrifice every male that first comes out of the womb. But I ransom my oldest sons.'
It will be a sign on your hand and a symbol on your forehead that the LORD brought us out of Egypt with great power."