This reminds me of the time a nice young Amalekite came to report Saul's death, thinking that I'd be glad to hear it. I killed him for it.
11 I'll do even worse to you, since you murdered a righteous man on his bed.
12 Then David commanded his young men and they killed Rechab and Baanah, cut off their hands and feet, and hung their bodies over the pool in Hebron. They buried Ishbosheth's head in the sepulcher of Abner.
David becomes king of Israel
5 All the tribes of Israel came to Hebron to anoint David as king.
4 David was thirty years old when he began to reign, and he was king for forty years.
David occupies Jerusalem, calling it "The City of David"
6 David and his men went to Jerusalem, but the Jebusites who lived there, said to him,
You won't be able to take this city, even the lame and the blind could stop you.
8 David said, "I hate lame and blind people. Whoever smites them will be my captain."
9 David took the city of Jerusalem, renaming it "The city of David."
Don't attack, at least not directly. Come around from behind, over by the mulberry trees. Wait until you hear the sound of the Philistines from the tops of the trees. Then come down and smite them. I'll attack them from the front.
25 David did as God commanded, and, with God's help, he smote the Philistines again.
A few more words about this episode
I left out verse 4:4, since it is out of place here. It is summarized below and will become relevant in 2 Sam 9.
Jonathan's son, Mephibosheth, was dropped by his nurse when she was fleeing after hearing about the deaths of Saul and Jonathan. The fall permanently injured the five-year-old boy's feet.
A nice young Amalekite came to report Saul's death (4:10)