John Gill Commentary Numbers 16:11

"Therefore thou and all thy company are gathered together against Jehovah: and Aaron, what is he that ye murmur against him?" — Numbers 16:11 (ASV)

For which cause, both [you] and all your company [are]
gathered together against the Lord
For gathering together against his ministers, whom he had put into office to act under him, and endeavouring to overturn a constitution of his erecting, and resisting and not submitting to an ordinance of his, is interpreted gathering against him, and acting in opposition to him; see (Romans 13:1Romans 13:2) ;

and what [is] Aaron, that you murmur against him ?
what is his transgression? what has he done? as Aben Ezra paraphrases it; he is not chargeable with any fault, he did not take upon him the office of high priest of himself, God called him to it, and put him in it; he is only his minister, and by no means to be blamed, and therefore it is unreasonable to envy him, or murmur against him; and, indeed, murmuring against him is murmuring against the Lord.