We read in 2 Samuel 20:1–3. The contention between the Israelite and Judean delegations at Gilgal became so heated that a Benjamite by the name of Sheba announced a revolutionary movement against David and led the Israelites to desert the king. David and the Judeans then continued their homeward journey to Jerusalem alone. Once there, David reasserted his monarchical claims by, among other things, regathering his harem (cf. 15:16). He provided for them, but remained sexually aloof because they had been appropriated by his son Absalom (16:21–22).
We read in 2 Samuel 20:4–10 of an urgent matter. It was clear to David that he must overcome the rouge movement that had been initiated by Sheba at Gilgal. So he ordered Amasa, his new commander (2 Samuel 19:13), to reorganize the army of Judah in three days so that Sheba might be brought to justice. When Amasa was unable to do so in the allotted time Abishai, at David’s command, took his own personal elite troops (2 Samuel 18:2) and set out for the North (2 Samuel 20:7).
On the way they met Amasa at Gibeon, about five miles north of Jerusalem. Joab, though having been demoted and replaced by Amasa, was present. Pretending to greet Amasa warmly, Joab killed him with his dagger. Thus Joab gained revenge for his loss of rank. What is particularly heinous is the fact that Joab and Amasa were cousins, sons of two of David’s half sisters (1 Chronicles 2:16–17). Again, then, the prophecy of Nathan came to pass: “The sword will never depart from your house” (2 Samuel 12:10).