2 Samuel 10:2 (BSB)

And David said, “I will show kindness to Hanun son of Nahash, just as his father showed kindness to me.” So David sent some of his servants to console Hanun concerning his father. But when they arrived in the land of the Ammonites,

From 2 Samuel 10. Also in the ESV.

Commentary on 2 Samuel 10:2

Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on 2 Samuel 10:1-5: Here is, I. The great respect David paid to his neighbour, the king of the Ammonites, Sa2 10:1, Sa2 10:2. 1. The inducement to it was some kindness he had formerly received from Nahash the deceased king. He showed kindness to me, says David (Sa2 10:2), and therefore (having lately had satisfaction in showing kindness to Mephibosheth for his father's sake) he resolves to show...
John Gill (Reformed Baptist), Exposition of the Old and New Testaments on 2 Samuel 10:2: Then said David, I will show kindness to Hanun the son of Nahash,.... Send him a friendly compliment of condolence on the death of his father: as his father showed kindness unto me; when David was persecuted by Saul, he sent him aid, and invited him into his country for protection it may be, and some way or other showed respect unto him; though not...
Geneva Bible Notes (Reformed), Geneva Bible Study Notes on 2 Samuel 10:2: Then said David, I will shew kindness unto Hanun the son of Nahash, as his father shewed kindness unto me. And David sent to comfort him by the hand of his servants for his father. And David's servants came into the land of the children of Ammon. (a) The children of God are not unmindful of a benefit received.
Adam Clarke (Methodist), Clarke's Commentary on the Bible on 2 Samuel 10:2: I will show kindness unto Hanun the son of Nahash - We do not know exactly the nature or extent of the obligation which David was under to the king of the Ammonites; but it is likely that the Nahash here mentioned was the same who had attacked Jabesh-gilead, and whom Saul defeated: as David had taken refuge with the Moabites, (Sa1 22:3), and this...