Komentaryo sa Job 37:12: Rashi

And he who is thus appointed.

turns around in circuits by His guidance [i.e., by the guidance] of the Omnipresent.

for their work namely, of the rains; for the work which is incumbent upon them to do, either good or evil, he is turned about with many circuits, as [the passage] that we learned (Rosh Hashanah 17b): if Israel were perfectly righteous on Rosh Hashanah so that [much] rain was decreed for them, and they should later become sinful—it would be impossible to decrease it [the amount of rain] because the decree would already have gone forth; but the Holy One, blessed be He, would let it come down out of its season and upon a land that did not require it. “And sometimes to do good”; how is this? etc.

whatever He commands them Those rains, to do on earth. [Another explanation: And he turns around in circuits with His guidance—He causes the clouds and the winds to encompass the mountains so that they should be watered from all sides. In the Aggadah of “Vehayah ekev” (Sifrei Ekev 39).]