Exodus 12

The final plague happens in this chapter. Every firstborn human and animal
of the outnumbered Egyptian population perishes. This finally convinces Pharoah to let the Israelites go.

This event is an occurrence God wants his people to observe and remember.
Israelites were given specific dietary commands, as well as instruction
to remember the current month as the first month of the year. They are instructed to honor the 14th and 21st days of the month as time to rest and to avoid eating yeast.

God details specific dietary instructions about preparing a meal for what
becomes the Passover feast. Non-compliance with the dietary instructions
regarding the Passover are a punishable offense. This is the second time God gave serious laws about consuming food since the fall of man.