Sifrei Bamidbar 47

(Bamidbar 7:10) "And the chiefs presented the inauguration (offerings) of the altar on the day that it was anointed": We are hereby apprised that just as the chiefs made donations for the work of the mishkan, so, they made donations for the inauguration of the altar. "And the chiefs presented": They came and stood before the altar and Moses did not accept (their offerings) from them until he was told by the Holy One: Let them present their offerings for the inauguration of the altar. And Moses still did not know in what order (of precedence) they should present them, if by (order of precedence in) the traveling (of the camps, in which instance Judah would present first) or by (order of) birth, (in which instance Reuven would present first), until he was told by the Holy One Blessed be He: Let them present by (the order of) traveling. And Moses still did not know how the chiefs would present, all together, or each in his day, until he was told by the Holy One: Let each one present in his day, as it is written (Ibid. 11) "each chief on his day": What is the intent of (the redundancy) "each chief on his day, each chief on his day"? Because Nachshon was (comparable to) a king, and he presented first, he should not say: Since I presented first, I should (also) present with each one on his day; it is, therefore, written "each chief on his day."