Now Moses gives a quick overview of Israelite history, talking about leaving Egypt, wandering in the wilderness, and defeating Og and Sihon. Deuteronomy is all about recaps.
The people have seen all of things that God has done, and they should be grateful for all of it.
The covenant, by the way, works for Moses's people and future generations, too. That means future generations will see the devastating results of idol worship. Because the Israelites abandoned their covenant with God, the destruction will be like Sodom and Gomorrah. Want to know how bad that is? Check out Genesis 19.