1 Chronicles 14:8

And when the Philistines heard that David was anointed king over all Israel, all the Philistines went up to seek David. And David heard of it, and went out against them.

All the Philistines went up to seek David. In the hope of accomplishing his ruin (for so the phrase is used, 1 Samuel 23:15; 1 Samuel 24:2) before his throne was consolidated. Their hostility arose, both from a belief that his patriotism would lead him, before long, to wipe out the national dishonour at Gilboa; and by fear, that in any invasion of their country, his thorough knowledge of their weak points would give him superior advantages. They resolved, therefore, to surprise and crush him ere he was fairly seated on his throne.