And the Spirit came upon Amasai, a captain of the thirty, and he said, Go, David, son of Jesse, thou and thy people, peace, peace be to thee, and peace to thy helpers, for thy God has helped thee. And David received them, and made them captains of the forces.
Some from Manasseh defected to David when he went with the Philistines to fight against Saul. (They did not help the Philistines because the Philistine rulers consulted and sent David away, saying, “It will cost us our heads if he defects to his master Saul.”)