David thought, "I will show kindness to Hanun son of Nahash, because his father showed kindness to me." So David sent a delegation to express his sympathy to Hanun concerning his father. When David's men came to Hanun in the land of the Ammonites to express sympathy to him,
the Ammonite nobles said to Hanun, "Do you think David is honoring your father by sending men to you to express sympathy? Haven't his men come to you to explore and spy out1 the country and overthrow it?"
References for 1 Chronicles 19:3
So Hanun seized David's men, shaved them, cut off their garments in the middle at the buttocks, and sent them away.
When someone came and told David about the men, he sent messengers to meet them, for they were greatly humiliated. The king said, "Stay at Jericho till your beards have grown, and then come back."
When the Ammonites realized that they had become a stench2 in David's nostrils, Hanun and the Ammonites sent a thousand talents of silver to hire chariots and charioteers from Aram Naharaim, Aram Maacah and Zobah.3
References for 1 Chronicles 19:6