The king of Ammon died, and David had a good relationship with him, so he send emissaries to comfort the new king after the loss of his father. In a classic example of ‘no good deed goes unpunished,’ the courtiers and princes in Ammon planted conspiratorial ideas in the new king’s head. They said something to the effect of implying that David actually sent the emissaries as spies rather than comforters. Hanun, the new king, was easily convinced. “And Hanun took David’s servants, and he shaved them, and he cut their garments in half up to their groin and he sent them away (Chronicles I 19:4).” This seems to have escalated the situation greatly, and in a really disgusting way. A gesture of goodwill was taken as sinister, which already says something sad about how easily Hanun was manipulated, and then he lashed out in a manner that was literally below the belt. It’s one thing to be concerned about someone, but to actively humiliate them just to make a point is beyond the pale in my mind.