1 Samuel 27:2
And David arose, and he passed over with the six hundred men that were with him unto Achish, the son of Maoch, king of Gath. And David arose, and he passed over with the six hundred men that were with him unto Achish, the son of Maoch, king of Gath.
The verse records David arising and passing over into Philistine territory with the six hundred men who were with him unto Achish, son of Maoch, king of Gath. He went to seek refuge and asylum among the Philistines because Saul relentlessly hunted him to kill him. He placed himself and his men under Philistine protection after his faith failed, acting without seeking the counsel of the Lord.
Though he knew God had chosen him to rule Israel, he would not lift his hand against Saul, whom God had anointed. Believing he would be safe from betrayal, he brought his family and household and possessions with him and appeared to settle permanently in Philistia. Achish promised protection to the fugitive Israelites.
Achish welcomed David partly from admiration for him and partly because his departure from Israel flattered his vanity, hoping his example would attract other Hebrews to his side. The Philistines welcomed him for their own advantage, hoping to draw his forces away from Saul's army and have him fight against Israel. His prudent, humble conduct brought peace with his enemies, and he remained among them until Saul's death. Repaying their favor with deception was poor policy.