Yahweh will render to every man his righteousness and his faithfulness; because Yahweh delivered you into my hand today, and I wouldn't put forth my hand against Yahweh's anointed.
David had borne witness twice to Saul’s guilt before God (chs. 24 and 26; cf. Numbers 35:30). God proceeded to put him to death not long after this (ch. 31). David became God’s instrument in passing judgment on Saul for his sin and so became a blessing to all Israel.