פּירוש אויף במדבר 1:4

ואתכם יהיו AND WITH YOU THERE SHALL BE [A MAN OF EVERY TRIBE] — when you number them there shall be with you the princes of each tribe.

“And with you there shall be a man from each tribe, a man who is the head of his father’s house.” Since it already said a man from each tribe, why did it repeat a man who is the head of his father’s house? It is reasonable to say that this is similar to what the commentators wrote on the verse Dan shall judge his people as one of the tribes of Israel (Genesis 49:16). This means that he [Dan] did not favor his own tribe, which was called his people, but rather he judged them as one of the tribes of Israel, treating them the same as any other tribe. Similarly, these tribal leaders were virtuous, and each one was a man for his tribe. Each leader acted with strength toward his entire tribe, exercising his leadership role with authority. And not only did he do this for those members of the tribe who were somewhat distant from him, but he was even the head of his father’s house — to those closest to him — he also served as their leader, exercising his authority over them.

איש ראש לבית אבותיו, this is emphasised to show that no one challenged the authority and authenticity of the people representing themselves as the “heads of his family.” When the count occurred, אתכם in the presence of the family heads each one testifying to the age of the individuals concerned, no one would dare to challenge the accuracy of the data provided by the family head.