1 Chronicles 19:2-8

2And David said, I will show kindness to Hanun the son of Nahash, because his father showed kindness to me. And David sent messengers to comfort him concerning his father. So the servants of David came into the land of the children of Ammon to Hanun, to comfort him. 3But the princes of the children of Ammon said to Hanun, Thinkest thou that David doth honour thy father, that he hath sent comforters to thee? are not his servants come to thee to search, and to overthrow, and to spy out the land?1 4Therefore Hanun took David’s servants, and shaved them, and cut off their garments in the middle, even to their buttocks, and sent them away. 5Then there went certain, and told David how the men were served. And he sent to meet them: for the men were greatly ashamed. And the king said, Tarry at Jericho until your beards are grown, and then return.

6And when the children of Ammon saw that they had made themselves odious to David, Hanun and the children of Ammon sent a thousand talents of silver to hire them chariots and horsemen out of Mesopotamia, and out of Syriamaachah, and out of Zobah.2 7So they hired thirty and two thousand chariots, and the king of Maachah and his people; who came and encamped before Medeba. And the children of Ammon gathered themselves together from their cities, and came to battle. 8And when David heard of it, he sent Joab, and all the host of the mighty men.