Albert Barnes Commentary Job 36:31

"For by these he judgeth the peoples; He giveth food in abundance." — Job 36:31 (ASV)

For by them he judges the people - By means of the clouds, the rain, the dew, the tempest, and the thunderbolt. The idea seems to be that he makes use of all these to execute his purposes on mankind. He can either make them the means of imparting blessings or of inflicting the severest judgments. He can cause the tornado to sweep over the earth; he can arm the forked lightning against the works of art; he can withhold rain and dew, and spread over a land the miseries of famine.

He gives food in abundance - That is, by the clouds, the dew, the rain. The idea is that he can send timely showers if he chooses, and the earth will be clothed with plenty. All these things are under his control, and he can, as he pleases, make them the means of comfort to man, or of punishing him for his sins; compare Psalms 65:11-13.