John Gill Commentary Numbers 2:20

"And next unto him shall be the tribe of Manasseh: and the prince of the children of Manasseh shall be Gamaliel the son of Pedahzur." — Numbers 2:20 (ASV)

And by him [shall be] the tribe of Manasseh
Who though the elder brother to Ephraim, yet Ephraim was preferred to him, and had a standard given him, and his elder brother was directed to pitch by it; and this being agreeably to the prophecy of Jacob, could not well be objected to; and Benjamin, the younger brother of Joseph, being placed under the standard of a son of his, that stood in his father's room, could not be offended; and these all being the descendants of Rachel, might well be thought to agree together, and be very well pleased with their situation:

and the captain of the children of Manasseh shall be Gamaliel the son
of Pedahzur ;
the same as in (Numbers 1:10) (7:54) .