What does Exodus 13:16 mean?

Every firstborn of a donkey you shall redeem with a lamb; and if you will not redeem it, then you shall break its neck; and you shall redeem all the firstborn of man among your sons.

It shall be, when your son asks you in time to come, saying, ‘What is this?’ that you shall tell him, ‘By strength of hand Yahweh brought us out from Egypt, from the house of bondage.

When Pharaoh stubbornly refused to let us go, Yahweh killed all the firstborn in the land of Egypt, both the firstborn of man, and the firstborn of livestock. Therefore I sacrifice to Yahweh all that opens the womb, being males; but all the firstborn of my sons I redeem.’

When Pharaoh had let the people go, God didn’t lead them by the way of the land of the Philistines, although that was near; for God said, “Lest perhaps the people change their minds when they see war, and they return to Egypt”;

but God led the people around by the way of the wilderness by the Red Sea; and the children of Israel went up armed out of the land of Egypt.

Moses took the bones of Joseph with him, for he had made the children of Israel swear, saying, “God will surely visit you, and you shall carry up my bones away from here with you.”