The history does not record any instance of Nahash's kindness to David, but the enmity of the house of Nahash against Saul may have disposed him favorably toward Saul's enemy David, and if there was any family connection between David's house and Nahash 2 Samuel 17:25 this may have increased the friendship.

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, (1 Samuel 22:3), and this was contiguous to the king of the Ammonites, his hatred to Saul might induce him to show particular kindness to David.

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 out of real love and friendship to David, but in enmity to Saul, who had defeated him at Jabeshgilead, and had often wars with him: the Jews say (o) the particular kindness was, that when David left his father, mother, and brethren, with the king of Moab, he slew all but one, who fled to the king of the children of Ammon, and was by him saved alive:

and David sent to comfort him by the hand of his servants for his father; for the death of his father; to condole the loss of him, which was the custom of kings in friendship and alliance in former times, and still continues:

and David's servants came into the land of the children of Ammon; even to Rabbah, the metropolis of the nation, and the royal city, where the king kept his court.

(o) Tanchuma apud Jarchium in loc.

Then said David, I will shew kindness unto Hanun the son of Nahash, as his father {a} 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.

10:2 David sent - There had hitherto been friendship between David and him: and therefore the spoils of the children of Ammon are mentioned, chap.8:12, by way of anticipation, and with respect to the story here following.

2. Then said David, I will show kindness unto Hanun the son of Nahash, as his father showed kindness unto me-It is probable that this was the Nahash against whom Saul waged war at Jabesh-gilead (1Sa 11:11). David, on leaving Gath, where his life was exposed to danger, found an asylum with the king of Moab; and as Nahash, king of the Ammonites, was his nearest neighbor, it may be that during the feud between Saul and David, he, through enmity to the former, was kind and hospitable to David.

10:1-5 Nahash had been an enemy to Israel, yet had showed kindness to David. David therefore resolves gratefully to return it. If a Pharisee gives alms in pride, though God will not reward it, yet he that receives the alms ought to return thanks for it. Those who bear ill-will to their neighbours, are resolved not to believe that their neighbours bear any good-will to them. There is nothing so well meant, but it may be ill interpreted, and is wont to be so, by men who love nobody but themselves. The best men must not think it strange if they are thus misrepresented. Charity thinketh no evil. According to the usages of those days and countries, Hanun treated David's ambassadors in the most contemptuous manner. David showed much concern for his servants. Let us learn not to lay unjust reproaches to heart; they will wear off, and turn only to the shame of those who utter or do them; while the reputation wrongfully hurt in a little time grows again, as these beards did. God will bring forth thy righteousness as the light, therefore wait patiently for him, Ps 37:6,7.