II Samuel - Chapter 20
Another Rebellion
A man from the Tribe of Benjamin named Sheva ben Bichri held a grudge that David (from the Tribe of Judah) had "usurped" the throne from Saul (a fellow Benjaminite). He refuted David's claim to the throne and called upon others to join him in his rebellion. (He either wanted to become king himself or perhaps to abolish the monarchy altogether.) Representatives from all Tribes except for Judah supported him.
David returned to Jerusalem. He supported the ten concubines who had been violated by Avshalom, but he no longer lived with them. One opinion in the Jerusalem Talmud is that it is prohibited for a king to continue to have relations with a woman who has been with another man, even by force. The other opinion is that, since this was a punishment for David's lack of restraint with Batsheva, he was repenting by showing restraint.
David summoned his new general, Amasa (who was either Yoav's deputy or replacement) and told him to assemble his forces and report in three days. Amasa went, but failed to return at the appointed time. David told Avishai (another general) that Sheva was potentially a bigger threat than Avshalom, so he took the army to defeat Sheva.
Amasa arrived at the site of the battle and Yoav went to greet him. But Yoav grabbed Amasa's beard, and jabbed his sword in by his fifth rib (Yoav's signature blow). His pretext was that Amasa had defied the king's order to return, but of course he was motivated by his own loss of position and prestige. Amasa dead, Yoav and Avishai took off after Sheva. Yoav's faithful soldiers tossed Amasa's body in a field and covered it with a blanket (or something). "Nothing to see here, folks! If you're for David, follow Yoav!"
(Just to keep a body count here, Yoav has now killed Avner, who defected to David's side, Avshalom, who David had ordered not be harmed, and Amasa, who David had appointed general. If you've had enough of Yoav, imagine how David must have felt. Stick around for I Kings and you'll see Yoav get his!)
They went to the walled city of Aveil, where Sheva had taken refuge. They started a siege, when a woman called out to Yoav. She asked why he was trying to destroy an innocent city without making overtures of peace. "G-d forbid!" he responded, "We just want Sheva ben Bichri." The woman assured Yoav that Sheva's head would shortly be flying over the wall to him. She told the people of the city of her arrangement and they gladly offered up Sheva. (Presumably they opted to execute him rather than turn him over alive so that he would not implicate them in their crimes.) Sheva dealt with, Yoav called off the siege and headed back to Jerusalem.
The Talmud derives a halacha from this incident. If enemies attack a city and say "Choose someone for us to kill" we may not single out a victim. But if they ask for a particular person, he may be handed over.
The chapter ends with an update of David's "command crew." Yoav was reinstated as commander of the army, a man named Adoram was in charge of taxation, and a man named Ira was David's "personal Kohein," to whom David would give all portions dues to Kohanim ("priests"). Again, we will see why this is important very soon.