In this chapter, Moses reminds the Israelites of their many past failings.
This chapter is written in the same style as the historical prologue from chapters 1-3, so its placement here is a bit peculiar. The way I understand this chapter is that it is another warning against pride. In the last chapter, Moses warned the people against pride when they come into the land and possess its riches. In this chapter, Moses warns the people to avoid pride when they dispossess the nations that already exist there, as the people might think "because of my righteousness the LORD has brought me in to possess this land".
Then Moses recounts their various failings in the past, from the golden calf of Ex 32 to the sin of Massah when the people quarreled with the LORD (Ex 17), to the sins of Taberah and Kibroth-hattavah in Num 11. Finally, Moses reminds the people of their rebellion against taking the promised land in Num 14.
I have discussed all of these events when they first occurred and more than once I have pointed out the Israelites' pattern of continued rebellion against the LORD. It's amazing that we can read of all these rebellions and it is all in the context of Israel "crossing over the Jordan today to go in [to the promised land]", and that the LORD would overthrow all of the fierce opposition that Israel can expect. But I guess that's the point of this chapter, to show the LORD's mercy in light of Israel's rebellion. Moses also paints himself very positively, as he intercedes for the people on several occasions.
I'm not sure what else I can say. These are all stories we have read before, and this chapter doesn't add anything new, except to put them all in the same place. Unlike the historical prologue in chapters 1-3, this chapter does not add any new material, so I have nothing else to add.