Numbers 1:4-16
And one man from each tribe, the head of each family, must be there with you. . . .

Numbers 7:2
And the leaders of Israel, the heads of their families, presented an offering. These men were the tribal leaders who had supervised the registration.

Exodus 18:21
Furthermore, select capable men from among the people--God-fearing, trustworthy men who are averse to dishonest gain. Appoint them over the people as leaders of thousands, of hundreds, of fifties, and of tens.

Deuteronomy 1:15
So I took the leaders of your tribes, wise and respected men, and appointed them as leaders over you--as commanders of thousands, of hundreds, of fifties, and of tens, and as officers for your tribes.