Sforno on Numbers 7:2/ספורנו על במדבר ז׳:ב׳

1הם נשיאי המטות, הם העומדים על הפקודים. Seeing they all occupied official positions the gift/offering each one brought was on behalf of his tribe and its members. Seeing each one was in charge of other people, he felt a sense of some members of his tribe being suspected of some misdemeanour. At the same time, seeing that they did not only represent the members of the tribes but were נשיאים, “princes” in their own right, they agreed to act as the interlocutors of their tribe in trying to obtain atonement for the errors committed by members of their tribe by offering a communal offering on their behalf.