John Gill Commentary Numbers 16:42

"And it came to pass, when the congregation was assembled against Moses and against Aaron, that they looked toward the tent of meeting: and, behold, the cloud covered it, and the glory of Jehovah appeared." — Numbers 16:42 (ASV)

And it came to pass, when the congregation was gathered
against Moses and against Aaron
To kill them, as the Targum of Jonathan adds; who, perhaps, upon uttering their murmurs, made up to them, and by their gestures showed an intention to murder them:

that they looked toward the tabernacle of the congregation ;
either the people did, to see whether they could observe any appearance of the displeasure of God against them; or rather Moses and Aaron looked that way for help and deliverance in this extreme danger, knowing there was no salvation for them but of the Lord, (Jeremiah 3:23) ;

and, behold, the cloud covered it ;
as when it was first erected, and which was a token of the divine Presence, (Numbers 9:15Numbers 9:16) ; perhaps it had dispersed immediately upon the death of the rebels, and now returned again in favour of the servants of the Lord:

and the glory of the Lord appeared ;
in the cloud, as in (Numbers 16:19) ; to encourage Moses and Aaron, and to deliver them out of the hands of the people, and to the terror of them.