2 Samuel 10:4

Shaved off. Such an insult could not be lightly accepted by Israel. It is a universal principle among nations that the person of an ambassador must be held inviolate. In heaping such aide indignities on David’s envoys, the Ammonites were openly asking for war. For some time they had been alarmed at David’s growing strength and had probably by now decided that the day of reckoning had come. But instead of starting hostilities themselves, they may have attempted, by this incident, to pursue a course that would make it appear that they were the ones who were attacked and aggrieved, so that they could claim the sympathy of their neighbors.

Cut off their garments. Appropriately, the envoys of David wore long robes. To cut off the bottom half of these outer robes, which subjected the wearer to shame and ridicule, was as much of an insult as cutting off their beards. The outrage to the ambassadors was an insult to the nation they represented.