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

[271] ABOUT this time it was that David heard how the Philistines had made an inroad into the country of Keilah, and robbed it; so he offered himself to fight against them, if God, when he should be consulted by the prophet, would grant him the victory. And when the prophet said that God gave a signal of victory, he made a sudden onset upon the Philistines with his companions, and he shed a great deal of their blood, and carried off their prey, and staid with the inhabitants of Keilah till they had securely gathered in their corn and their fruits. However, it was told Saul the king that David was with the men of Keilah; for what had been done and the great success that had attended him, were not confined among the people where the things were done, but the fame of it went all abroad, and came to the hearing of others, and both the fact as it stood, and the author of the fact, were carried to the king's ears. Then was Saul glad when he heard David was in Keilah; and he said, "God hath now put him into my hands, since he hath obliged him to come into a city that hath walls, and gates, and bars." So he commanded all the people suddenly, and when they had besieged and taken it to kill David. But when David perceived this, and learned of God that if he staid there the men of Keilah would deliver him up to Saul, he took his four hundred men and retired into a desert that was over against a city called Engedi. So that when the king heard he was fled away from the men of Keilah, he left off his expedition against him.