The Philistines gathered their whole army together at Aphek. Israel's army camped by the spring of water at Jezreel.
References for 1 Samuel 29:1
The Philistine rulers marched out in companies of hundreds and thousands. David and his men were marching with Achish behind the others.
The commanders of the Philistines asked, "Why are these Hebrews here?" Achish replied, "That's David, isn't it? Wasn't he an officer of Saul, the king of Israel? He has already been with me for more than a year. I haven't found any fault in him. That's been true from the day he left Saul until now."
But the Philistine commanders were angry with Achish. They said, "Send David back. Let him return to the town you gave him. He must not go with us into battle. If he does, he'll turn against us during the fighting. In fact, he might even cut off the heads of our own men. What better way could he choose to win back his master's favor?
Isn't David the one the Israelites sang about when they danced? They sang, " 'Saul has killed thousands of men. David has killed tens of thousands.' "
So Achish called David over to him. He said, "You have been faithful to me. And that's just as sure as the LORD is alive. I would be pleased to have you serve with me in the army. I haven't found any fault in you. That's been true from the day you came to me until now. But the Philistine rulers aren't pleased to have you come along.
So go back home in peace. Don't do anything that wouldn't please the Philistine rulers."
"But what have I done?" asked David. "What have you found against me from the day I came to you until now? Why can't I go and fight against your enemies? After all, you are my king and master."
Achish answered, "You have been as pleasing to me as an angel of God. But the Philistine commanders have said, 'We don't want David to go up with us into battle.'
So get up early in the morning. Take with you the men who used to serve Saul. Leave as soon as the sun begins to come up."
So David and his men got up early in the morning. They went back to the land of the Philistines. And the Philistines went up to Jezreel.