Moses gives speeches about laws and the importance of following God before the Israelites enter the Promised Land.
And the LORD shall do unto them as he did to Sihon and to Og, kings of the Amorites, and unto the land of them, whom he destroyed.
And God will treat them like how he treated Sihon and Og, the kings who ruled the Amorites, and also their land, which he completely destroyed.