Therefore there had hitherto been peace and friendship between David and him; and therefore the spoils of the children of Ammon are mentioned 2 Samuel 8:12, by way of anticipation, and with respect to the story here following. As his father showed kindness unto me; which he might do either by offering him his help, if he needed it; or by supplying him with military or other provisions upon occasion, or many other ways.
Related Commentaries of 2 Samuel 10:2
2 Samuel 10:2
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.