1 Chronicles 19:2

19:2 David said, “I will express my loyalty to Hanun son of Nahash, for his father was loyal to me.” So David sent messengers to express his sympathy over his father’s death. When David’s servants entered Ammonite territory to visit Hanun and express the king’s sympathy,

1 Chronicles 19:19

19:19 When Hadadezer’s subjects saw they were defeated by Israel, they made peace with David and became his subjects. The Arameans were no longer willing to help the Ammonites.