The Egyptian here uses a common term for referring to God or the gods. He wants David to swear to the God that David believes in before he takes him to the camp. Apart from David’s word, he has no guarantee that David won’t simply hand him over to his old master in exchange for some kind of a reward. David’s must have agreed to take an oath since the man proceeded to lead them to the Amalekite camp.1
15 David lui dit: Veux-tu me faire descendre vers cette troupe? Et il répondit: Jure-moi par le nom de Dieu que tu ne me tueras pas et que tu ne me livreras pas à mon maître, et je te ferai descendre vers cette troupe.