Matthew Henry Commentary Numbers 11:4-9

"And the mixed multitude that was among them lusted exceedingly: and the children of Israel also wept again, and said, Who shall give us flesh to eat? We remember the fish, which we did eat in Egypt for nought; the cucumbers, and the melons, and the leeks, and the onions, and the garlic: but now our soul is dried away; there is nothing at all save this manna to look upon. And the manna was like coriander seed, and the appearance thereof as the appearance of bdellium. The people went about, and gathered it, and ground it in mills, or beat it in mortars, and boiled it in pots, and made cakes of it: and the taste of it was as the taste of fresh oil. And when the dew fell upon the camp in the night, the manna fell upon it." — Numbers 11:4-9 (ASV)

Man, having forsaken his proper rest, feels uneasy and wretched, even when prosperous. They were weary of the provision God had made for them, even though it was wholesome and nourishing food. It cost no money or care, and the labor of gathering it was very little indeed; yet they talked of Egypt's cheapness and the fish they ate there freely, as if that cost them nothing, when they paid dearly for it with hard service!

While they lived on manna, they seemed exempt from the curse sin had brought on man, that in the sweat of his face he should eat bread; yet they spoke of it with scorn. Peevish, discontented minds will find fault with what has no fault in it, except that it is too good for them. Those who could be happy often make themselves miserable through discontent.

They could not be satisfied unless they had meat to eat. It is evidence of the dominion of the carnal mind when we desire the delights and satisfactions of the senses. We should not indulge in any desire that we cannot in faith turn into prayer, as we cannot when we ask meat for our lust. What is lawful in itself becomes evil when God does not allot it to us, yet we still desire it.