Even though David isn't dead yet (and won't die until the beginning of 1 Kings), this chapter begins with David's last words.
The actual "last words" begin by saying that they're the last words of David, God's favorite.
David says that the spirit of God speaks through him, saying that a ruler who rules his people justly is like sunlight in the morning, or like a sun in a cloudless sky, its light gleaming off of the recently fallen rain on the land.
He asks rhetorically if his house isn't a bit like this ideal image of just rulership. In the end, he says, godless people are like so many thorns that are picked up with a spear and then burned.
The rest of the chapter proceeds with a long list of all David's best warriors.
These include Josheb Basshebeth, who once killed eight hundred men at one time. He was the head of a unit of three elite warriors, including Eleazar son of Dodo—who fought ferociously against the Philistines—and Shamah, who also fought against the Philistines successfully.
The three warriors did bold things, like sneaking behind enemy lines to get a drink for David—which he was too embarrassed to drink, and so offered it to God.
Abishai, says the narrator, was a great warrior—though not quite equal to the Three.
Another warrior, Benaiah, accomplished amazing feats, like killing a ferocious lion and a fearsome Egyptian. He later was the head of David's bodyguard.