Jamieson, Fausset and Brown on Amos 7:4

4. called to contend--that is, with Israel judicially (Job 9:3; Is 66:16; Eze 38:22). He ordered to come at His call the infliction of punishment by "fire" on Israel, that is, drought (compare Am 4:6-11), [Maurer]. Rather, war (Nu 21:28), namely, Tiglath-pileser [Grotius].

devoured the ... deep--that is, a great part of Israel, whom he carried away. Waters are the symbol for many people (Re 17:15).

did eat up a part--namely, all the land (compare Am 4:7) of Israel east of Jordan (1Ch 5:26; Is 9:1). This was a worse judgment than the previous one: the locusts ate up the grass: the fire not only affects the surface of the ground, but burns up the very roots and reaches even to the deep.