Walk through Amos, verse by verse, with the great Bible Commentaries of Matthew Henry (1662 - 1714) & Adam Clarke (1760 - 1832)
7:2
And it came to pass, that when they had made an end of eating the grass of the land, then I said, O Lord GOD, forgive, I beseech thee: by whom shall Jacob arise? for he is small. KJV
{ And it was done, when he had ended for to eat the herb of (the) earth, I said, Lord God, I beseech, be thou merciful; who shall raise Jacob, for he is little?} Wycliffe's Bible
By whom shall Jacob arise? - The locusts, the symbols of the many enemies that had impoverished
Jerusalem, having devoured much of the produce of the land, were proceeding, till, at the intercession of the prophet, they were removed. Then, seeing in the light of prophecy the nation in every sense brought low, he cries, "By whom shall Jacob arise? for he is small." Calmet justly remarks: "After the death of Jeroboam the second, the kingdom, so flourishing and powerful before, was reduced to such weakness that it was obliged to have recourse to strangers for support.
God formed these grasshoppers, not only as they were his creatures (and much of the wisdom and power of God appears in the formation of minute animals, as much in the structure of an ant as of an elephant), but as they were instruments of his wrath.