After a severe drought David hands over Saul's descendants to the Gibeonites as an atonement for what Saul had done
2 Samuel 21:1-6 (KJV)
1 Then there was a famine in the days of David three years, year after year; and David inquired of the LORD. And the LORD answered, It is for Saul, and for his bloody house, because he slew the Gibeonites. 2 And the king called the Gibeonites, and said unto them; (now the Gibeonites were not of the children of Israel, but of the remnant of the Amorites; and the children of Israel had sworn unto them: and Saul sought to slay them in his zeal to the children of Israel and Judah.) 3 Wherefore David said unto the Gibeonites, What shall I do for you? and wherewith shall I make the atonement, that ye may bless the inheritance of the LORD? 4 And the Gibeonites said unto him, We will have no silver nor gold of Saul, nor of his house; neither for us shalt thou kill any man in Israel. And he said, What ye shall say, that will I do for you. 5 And they answered the king, The man that consumed us, and that devised against us that we should be destroyed from remaining in any of the coasts of Israel, 6 Let seven men of his sons be delivered unto us, and we will hang them up unto the LORD in Gibeah of Saul, whom the LORD did choose. And the king said, I will give them.
But a few years before David had sworn an oath to Saul that he will not destroy & cut off his seed.
1 Samuel 24:16-22 (KJV)
16 And it came to pass, when David had made an end of speaking these words unto Saul, that Saul said, Is this thy voice, my son David? And Saul lifted up his voice, and wept. 17 And he said to David, Thou art more righteous than I: for thou hast rewarded me good, whereas I have rewarded thee evil. 18 And thou hast showed this day how that thou hast dealt well with me: forasmuch as when the LORD had delivered me into thine hand, thou killedst me not. 19 For if a man find his enemy, will he let him go well away? wherefore the LORD reward thee good for that thou hast done unto me this day. 20 And now, behold, I know well that thou shalt surely be king, and that the kingdom of Israel shall be established in thine hand. 21 Swear now therefore unto me by the LORD, that thou wilt not cut off my seed after me, and that thou wilt not destroy my name out of my father's house. 22 And David sware unto Saul. And Saul went home; but David and his men gat them up unto the hold.
Was this not a violation of his oath which he had sworn to the king when he handed over the seven descendants of Saul?