'Ritual' in the Bible

When you enter the land that the LORD will give you, just as he promised, you are to observe this ritual.

And when your children say to you, "What does this ritual mean?'

When the LORD brings you to the land of the Canaanite, the Hittite, the Amorite, the Hivite, and the Jebusite, which he swore to your ancestors to give you a land flowing with milk and honey you are to observe this ritual in this month.