II Sam. 10:1-19; I Chron. 19:1-19
David had been friends with Nahash, king of Ammon. At Nahash’s death, David as a good neighbor sent messengers to express his condolences to the new king, Hanun, the late king’s son. That was misunderstood as a spy mission. They partially shaved David’s men’s beards and shamefully cut their clothing. The insult to those men was also an insult to David since he had sent them on their mission.
One did not insult the king without serious repercussions. Hanun’s actions were considered an act of war. He assembled his own army and hired an army of chariots and horsemen from Syria.
Joab, the commander of Israel’s army was sent to fight against the Ammonites and Hanun’s hired army. With his confidence in God, Joab divided his army into two groups with his brother, Abishai being in charge of the second command. They were victorious as their enemies fled.
In a later battle, the Syrians were bitterly defeated by David’s army. In their defeat, they severed their ties with the Ammonites, made friends with David and served him.