Numbers 32:11-12 Surely none of the men that came up out of Egypt, from twenty years old and upward, shall see the land which I share unto Abraham, unto Isaac, and unto Jacob; because they have not wholly followed me: Save Caleb the son of Jephunneh the Kenezite, and Joshua the son of Nun, for they have wholly followed the Lord.
When the tribes of Reuben, Gad, and half of Manasseh settled on the conquered land east of the Jordan, Moses was afraid they might not cross over to fight with the rest of Israel. If so, they would discourage the heart of children of Israel. Moses then recounted how their fathers, the ten spies, discouraged Israel from entering the land. Thus none of them would see the Promised Land, from the age of twenty and upward. Their punishment was because they could not believe God, trust the Lord, or courageously follow Him