Albert Barnes Commentary Malachi 3:11

"And I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast its fruit before the time in the field, saith Jehovah of hosts." — Malachi 3:11 (ASV)

And I will rebuke the devourer—the locust, caterpillar, or any like scourge of God. It might be that when the rain watered the fields, the locust, caterpillar, or other such things might destroy the grain, so that the labors of man might perish; therefore he adds, I will rebuke the devourer. Neither shall your vine cast her fruit before the time, holding out a fair promise, but cut off by the frost-wind or the hail; the blossoms or the unripe fruit strewing the earth, as a token of God’s displeasure.