1 Chronicles 12:19

And there fell some of Manasseh to David
Of the tribe of Manasseh; they took his part, and on his side, and joined him:

when he came with the Philistines against Saul to battle;
which was a strong proof of their cordial attachment to him:

but they helped them not:
the Philistines; neither David nor his men, nor the Manassites that joined them:

for the lords of the Philistines, upon advisement;
counsel taken among themselves: sent him away; that is, David and his men:

saying, he will fall to his master Saul, to the jeopardy of our heads;
meaning, that he would go off with his troops to Saul, and betray them into his hands, and with their heads make his peace with him, see ( 1 Samuel 29:4 ) .