1 Chronicles 12:19 AMP

[19] Some [of the men] of Manasseh also defected to David when he came with the Philistines to go to battle against Saul. But David’s men did not [actually] assist the Philistines, for the lords (governors) of the Philistines after consultation sent him away, saying, “At the cost of our heads he may defect to his master Saul.”