2 Samuel 10:3-7

the commanders of the Ammonites said to their lord Hanun, “Do you think that David is simply honoring your father since he has sent you servants to console you? Has David not sent his servants to you in order to explore the city, to spy it out and overthrow it?”

So Hanun took David’s servants and shaved off half of their beards, and cut off their robes in the middle as far as their buttocks, and sent them away.

When messengers informed David, he sent servants to meet them, because the men were extremely humiliated. And the king said, “Stay in Jericho until your beards grow back, and then you shall return.”

Now when the sons of Ammon saw that they had become repulsive to David, the sons of Ammon sent messengers and hired the Arameans of Beth-rehob and the Arameans of Zobah, twenty thousand foot soldiers, and the king of Maacah with a thousand men, and the men of Tob with twelve thousand men.

When David heard about this, he sent Joab and all the army, the warriors.