Exodus 18:21-22, 25-26

But choose some capable men from among the people—men who respect God, who can be trusted, and who will not change their decisions for money. Make these men officers over the people, to rule over groups of thousands, hundreds, fifties, and tens. Let these officers solve the disagreements among the people all the time. They can bring the hard cases to you, but they can decide the simple cases themselves. That will make it easier for you, because they will share the work with you.

He chose capable men from all the Israelites and made them leaders over the people; they were officers over groups of thousands, hundreds, fifties, and tens. These officers solved disagreements among the people all the time. They brought the hard cases to Moses, but they decided the simple cases themselves.