Civil war broke out in Israel between Saul and his son-in-law David; the troops which should have been employed in resisting the common enemy were used in pursuing David, and David himself took service as a mercenary under Achish, King of Gath.
Saul and his sons fell in battle on Mount Gilboa; the relics of the Israelitish army fled across the Jordan, and the Philistine again ruled supreme on the western side of the Jordan.

David was allowed to govern Judah as a tributary vassal of the Philistine "lords." The murder of the feeble scion of Saul's house who had the name of king on the eastern side of the Jordan put an end to all this.

David threw off his allegiance to the Philistines, and was crowned King of Israel.
This act of open defiance was speedily followed by the invasion of Judah.

At first the war went against the Israelitish king; he was forced to fly from his capital, Hebron, and take refuge in an inaccessible cavern.

Here he organised his forces, and at last ventured into the field.