Psalm 60:7

The territorial allotment for the tribe of Manasseh, the firstborn of Joseph, was allocated first to Machir the firstborn of Manasseh and father of Gilead. Since he had been a man of war, Gilead and Bashan were allocated to him.

So David received them and assigned them to be officers over troops. Some of the descendants of Manasseh joined David when he was going to fight against Saul, accompanied by the Philistines. Even so, David was of no help to them, because the Philistine rulers were counseled to send him away. They told themselves, "He's going to go over to his master Saul at the cost of our heads."

May the firstborn of his bull be honorable to him, and may his horns be those of a wild ox. With them may he push people all together, to the ends of the earth. These are the myriads of Ephraim and the thousands of Manasseh."

David told Achish, "Very well, you will now see what your servant will do." Achish told David, "Very well, I'll appoint you as my permanent bodyguard."