He said to his men, Yahweh forbid that I should do this thing to my lord, Yahweh's anointed, to put forth my hand against him, seeing he is Yahweh's anointed.
It is interesting that God prevented David’s enemies from assassinating him later when he was Israel’s king (cf. Galatians 6:7). Compare also Jesus’ refusal to take vengeance on His enemies (Luke 23:34).