Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[205] HOWEVER, Saul was not disposed to persevere long in the state wherein he was, for when he saw that David was in great esteem, both with God and with the multitude, he was afraid; and being not able to conceal his fear as concerning great things, his kingdom and his life, to be deprived of either of which was a very great calamity, he resolved to have David slain, and commanded his son Jonathan and his most faithful servants to kill him: but Jonathan wondered at his father's change with relation to David, that it should be made to so great a degree, from showing him no small good-will, to contrive how to have him killed. Now, because he loved the young man, and reverenced him for his virtue, he informed him of the secret charge his father had given, and what his intentions were concerning him. However, he advised him to take care and be absent the next day, for that he would salute his father, and, if he met with a favorable opportunity, he would discourse with him about him, and learn the cause of his disgust, and show how little ground there was for it, and that for it he ought not to kill a man that had done so many good things to the multitude, and had been a benefactor to himself, on account of which he ought in reason to obtain pardon, had he been guilty of the greatest crimes; and "I will then inform thee of my father's resolution." Accordingly David complied with such an advantageous advice, and kept himself then out of the king's sight.