John Gill Commentary Numbers 14

And all the congregation lifted up their voice and cried
This is not to be understood of every individual in the congregation of Israel, but of the princes, heads, and elders of the people that were with Moses and Aaron when the report of the spies was made; though indeed the report might quickly spread throughout the body of the people, and occasion a general outcry, which was very loud and clamorous, and attended with all the signs of distress imaginable, in shrieks and tears and lamentations:

and the people wept that night :
perhaps throughout the night; could get no sleep nor rest all the night, but spent it in weeping and crying, at the thought of their condition and circumstances, and the disappointments they had met with, as they conceived, of entering into and possessing the land.

And all the children of Israel murmured against Moses, and
against Aaron
They being the instruments of bringing them out of Egypt, and conducting them hither:

and the whole congregation said unto them ;
some of them, the rest assenting to it by their cries and tears and gestures;

would God we had died in the land of Egypt ;
and then what they left behind they thought might have come into the hands of their children or relations; but now they concluded it would become a prey to the Canaanites:

or would God we had died in this wilderness ;
the wilderness of Paran, at Taberah, where many of them had been destroyed by fire, (Numbers 11:1–3) , and now they wish they had perished with them.

Wherefore has the Lord brought us unto this land
Unto the borders of it: their murmuring did not cease at Moses and Aaron, the instruments, but proceeded against God himself, who had done such wonderful things for them, not only in bringing them out of Egypt, but since they had been in the wilderness; and yet so ungrateful to complain of him and argue with him about favours bestowed on them, as if they were injuries done to them; and particularly as if God had no other intention in bringing them out of Egypt to the place where they were, but to fall by the sword :
the sword of the Canaanites, as the Targum of Jonathan adds:

that our wives and our children shall be a prey ?
to the same people; they supposed they should be killed, their wives abused, and their children made slaves of:

were it not better for us to return into Egypt ?
and so escape the hands of the inhabitants of Canaan, of whom they had terrible apprehensions from the report made of them.

And they said one to another, let us make a captain
An head over them instead of Moses, who they knew would never take the government and care of them, should they resolve to return to Egypt as they proposed, and besides were now so disaffected to him, that they might not care he should. Captains they had over their several tribes, but they chose to have one chief commander and general over them all; Nehemiah says they did appoint one; which they either actually did, or this proposal was interpreted as if really put in execution, they being so desirous of it, and bent upon it; wherefore their will is taken for the deed, and so understood; see (Nehemiah 9:17) ;

and let us return into Egypt :
which was downright madness, as some interpreters have justly observed; they must not only expect to be deserted by Moses, through whose means so many miracles had been wrought for them, and who was so wise and faithful a governor of them; and by Aaron their priest, who offered their sacrifices, and prayed for them, and blessed them; and by such a valiant general as Joshua, who had fought for them against their enemies; but by the Lord himself.

So that they could not expect the manna to be continued as food for them, nor the pillar of cloud and fire as a guide unto them, nor to be protected from their enemies, on the borders of whose countries they must pass; so that their destruction in the wilderness seemed inevitable; and if they could have surmounted these and other difficulties, what manner of reception could they expect to find in Egypt, on whose account all the firstborn of man and beast among them were slain, whom they had spoiled of their riches, and whose king and his army, and in it perhaps the, flower of the nation, were drowned in the Red sea, for their sakes? What therefore could they think of, if they had any sober thought at all, but utter ruin, should they return there again?

Then Moses and Aaron fell on their faces Through shame and confusion of face for them, at hearing so shocking a proposal made, and such wretched ingratitude expressed; they blushed at it, and were in the utmost distress on account of it, and therefore threw themselves into this posture; or it may be this was done either to beg of them that they would lay aside all thoughts of this kind, or to supplicate the divine Majesty that he would convince them of their sin and folly, and give them repentance for it and forgiveness of it; and this they did before all the assembly of the congregation of the children of Israel; to affect them the more with a sense of their sin and danger.