1SA 29:4

4 But the Philistia army commanders were angry with Achish [for allowing David’s army to be going with them]. They said to him, “Send David [and his men] back to the city that you gave to him! We do not want him to go with us into the battle. [If he goes with us,] we will have an enemy in our own midst! He would please King Saul by killing our own soldiers [RHQ]!