As the Israelites did not trust God's conduct, God ruled none of them would enter the promised land. Only their children would. (Deut. 1: 34-36) Deut. 2: 14-16 confirms the outcome.
From Deut. 5 on, Moses sums up the events from the exodus until then, recapitulates the law and renews the covenant. Doing this, he repeatedly adresses the people as if they have been eyewitnesses (Deut. 5: 5 etc.). Consider Deut. 29: 2-3:
2 Moses summoned all the Israelites and said to them: Your eyes have seen all that the Lord did in Egypt to Pharaoh, to all his officials and to all his land. 3 With your own eyes you saw those great trials, those signs and great wonders.
How does that go together? Until when has the first generation died?