1 Samuel 28:1-2
1 Samuel 28:1-2 NIV
In those days the Philistines gathered their forces to fight against Israel. Achish said to David, “You must understand that you and your men will accompany me in the army.” David said, “Then you will see for yourself what your servant can do.” Achish replied, “Very well, I will make you my bodyguard for life.”