My brethren have dealt deceitfully as a {k} brook, and as the stream of brooks they pass away;

(k) He compares friends who do not comfort us in our misery to a brook which in summer when we need water is dry, in winter is hard frozen and in the time of rain when we have no need overflows with water.

Wesley's Notes

6:15 Brethren - Friends; for though Eliphaz only had spoken, the other two shewed their approbation of his discourse. Deceitfully - Adding to the afflictions which they said they came to remove. And it is no new thing, for even brethren to deal deceitfully. It is therefore our wisdom to cease from man. We cannot expect too little from the creature, or too much from the creator.

Jamieson-Fausset-Brown Bible Commentary

15. Those whom I regarded as "my brethren," from whom I looked for faithfulness in my adversity, have disappointed me, as the streams failing from drought-wadies of Arabia, filled in the winter, but dry in the summer, which disappoint the caravans expecting to find water there. The fulness and noise of these temporary streams answer to the past large and loud professions of my friends; their dryness in summer, to the failure of the friendship when needed. The Arab proverb says of a treacherous friend, "I trust not in thy torrent" (Isa 58:11, Margin).

stream of brooks-rather, "the brook in the ravines which passes away." It has no perpetual spring of water to renew it (unlike "the fountain of living waters," Jer 2:13; Isa 33:16, at the end); and thus it passes away as rapidly as it arose.

Matthew Henry's Concise Commentary

6:14-30 In his prosperity Job formed great expectations from his friends, but now was disappointed. This he compares to the failing of brooks in summer. Those who rest their expectations on the creature, will find it fail when it should help them; whereas those who make God their confidence, have help in the time of need, Heb 4:16. Those who make gold their hope, sooner or later will be ashamed of it, and of their confidence in it. It is our wisdom to cease from man. Let us put all our confidence in the Rock of ages, not in broken reeds; in the Fountain of life, not in broken cisterns. The application is very close; for now ye are nothing. It were well for us, if we had always such convictions of the vanity of the creature, as we have had, or shall have, on a sick-bed, a death-bed, or in trouble of conscience. Job upbraids his friends with their hard usage. Though in want, he desired no more from them than a good look and a good word. It often happens that, even when we expect little from man, we have less; but from God, even when we expect much, we have more. Though Job differed from them, yet he was ready to yield as soon as it was made to appear that he was in error. Though Job had been in fault, yet they ought not to have given him such hard usage. His righteousness he holds fast, and will not let it go. He felt that there had not been such iniquity in him as they supposed. But it is best to commit our characters to Him who keeps our souls; in the great day every upright believer shall have praise of God.