1 Samuel 29:1
Now the Philistines gathered together all their armies to Aphek: and the Israelites pitched by a fountain which is in Jezreel. Now the Philistines gathered together all their armies to Aphek: and the Israelites pitched by a fountain which is in Jezreel.
The verse fixes the position of the two armies just before the coming battle, with all the Philistine armies gathered together at Aphek and the Israelites pitched by the fountain or spring that is in Jezreel. David had marched with the Philistines to this battlefield, yet he did not take part in the fighting.
He was caught between opposing pressures, for to fight for the Philistines would have made him a traitor to his own people Israel and to God. To withdraw from them, on the other hand, would have looked cowardly and ungrateful toward Achish, who had given him protection. The way out came when the Philistine rulers refused to allow David to go with their army into the fight, because they feared he might turn against them in the midst of battle to aid Israel.