According as we listened to Moses in all things, so will we listen to you: only Yahweh your God be with you, as he was with Moses.
Jesus said, "If any man would be chief among you, let him be the servant of all"( Mark 10:44 ). So a true minister is a man who is there not to be ministered to, but who is there to serve the needs of the people. So when it reads that he was Moses' servant, or his minister, it means that he was Moses' personal servant. He accompanied Moses, he helped Moses do the things, and Moses was, he was just his valet sort of, just his servant.