A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
job 8:2THE ADDRESS OF BILDAD. (Job 8:1-22)
like a . . . wind?--disregarding restraints, and daring against God.
job 8:3The repetition of "pervert" gives an emphasis galling to Job (Job 34:12). "Wouldst thou have God," as thy words imply, "pervert judgment," by letting thy sins go unpunished? He assumes Job's guilt from his sufferings.
job 8:4If--Rather, "Since thy children have sinned against Him, and (since) He has cast them away (Hebrew, by the hand of) for their transgressions, (yet) if thou wouldst seek unto God, &c., if thou wert pure, &c., surely [even] now He would awake for thee." UMBREIT makes the apodosis to, "since thy children," &c., begin at "He has cast them away." Also, instead of "for," "He gave them up to (literally, into the hand of) their own guilt." Bildad expresses the justice of God, which Job had arraigned. Thy children have sinned; God leaves them to the consequence of their sin; most cutting to the heart of the bereaved father.
job 8:5seek unto God betimes--early. Make it the first and chief anxiety (Psa 78:34; Hos 5:15; Isa 26:9; Pro 8:17; Pro 13:24).
job 8:6He would awake for thee--that is, arise to thy help. God seemed to be asleep toward the sufferer (Psa 35:23; Psa 7:6; Isa 51:9).
make . . . prosperous--restore to prosperity thy (their) righteous habitation. Bildad assumes it to have been heretofore the habitation of guilt.
job 8:7thy beginning--the beginning of thy new happiness after restoration.
latter end-- (Job 42:12; Pro 23:18).
job 8:8The sages of the olden time reached an age beyond those of Job's time (see on Job 42:16), and therefore could give the testimony of a fuller experience.
job 8:9of yesterday--that is, a recent race. We know nothing as compared with them because of the brevity of our lives; so even Jacob (Gen 47:9). Knowledge consisted then in the results of observation, embodied in poetical proverbs, and handed down by tradition. Longevity gave the opportunity of wider observation.
a shadow-- (Psa 144:4; Ch1 29:15).
job 8:10teach thee-- Job 6:24 had said, "Teach me." Bildad, therefore, says, "Since you want teaching, inquire of the fathers. They will teach thee."
utter words--more than mere speaking; "put forth well-considered words."
out of their heart--from observation and reflection; not merely, from their mouth: such, as Bildad insinuates, were Job's words. Job 8:11-13 embody in poetic and sententious form (probably the fragment of an old poem) the observation of the elders. The double point of comparison between the ungodly and the paper-reed is: 1. the luxuriant prosperity at first; and, 2. the sudden destruction.
job 8:11rush--rather, "paper-reed": The papyrus of Egypt, which was used to make garments, shoes, baskets, boats, and paper (a word derived from it). It and the flag, or bulrush, grow only in marshy places (such as are along the Nile). So the godless thrives only in external prosperity; there is in the hypocrite no inward stability; his prosperity is like the rapid growth of water plants.
job 8:12not cut down--Before it has ripened for the scythe, it withers more suddenly than any herb, having no self-sustaining power, once that the moisture is gone, which other herbs do not need in the same degree. So ruin seizes on the godless in the zenith of prosperity, more suddenly than on others who appear less firmly seated in their possessions [UMBREIT] (Psa 112:10).
job 8:13paths--so "ways" (Pro 1:19).
all that forget God--the distinguishing trait of the godless (Psa 9:17; Psa 50:22).
job 8:14cut off--so GESENIUS; or, to accord with the metaphor of the spider's "house," "The confidence (on which he builds) shall be laid in ruins" (Isa 59:5-6).
job 8:15he shall hold it fast--implying his eager grasp, when the storm of trial comes: as the spider "holds fast" by its web; but with this difference: the light spider is sustained by that on which it rests; the godless is not by the thin web on which he rests. The expression, "Hold fast," properly applies to the spider holding his web, but is transferred to the man. Hypocrisy, like the spider's web, is fine-spun, flimsy, and woven out of its own inventions, as the spider's web out of its own bowels. An Arab proverb says, "Time destroys the well-built house, as well as the spider's web."
job 8:16before the sun--that is, he (the godless) is green only before the sun rises; but he cannot bear its heat, and withers. So succulent plants like the gourd (Jon 4:7-8). But the widespreading in the garden does not quite accord with this. Better, "in sunshine"; the sun representing the smiling fortune of the hypocrite, during which he wondrously progresses [UMBREIT]. The image is that of weeds growing in rank luxuriance and spreading over even heaps of stones and walls, and then being speedily torn away.
job 8:17seeth the place of stones--Hebrew, "the house of stones"; that is, the wall surrounding the garden. The parasite plant, in creeping towards and over the wall--the utmost bound of the garden--is said figuratively to "see" or regard it.
job 8:18If He (God) tear him away (properly, "to tear away rapidly and violently") from his place, "then it [the place personified] shall deny him" (Psa 103:16). The very soil is ashamed of the weeds lying withered on its surface, as though it never had been connected with them. So, when the godless falls from prosperity, his nearest friends disown him.
job 8:19Bitter irony. The hypocrite boasts of joy. This then is his "joy" at the last.
and out of the earth--others immediately, who take the place of the man thus punished; not godly men (Mat 3:9). For the place of the weeds is among stones, where the gardener wishes no plants. But, ungodly; a fresh crop of weeds always springs up in the place of those torn up: there is no end of hypocrites on earth [UMBREIT].
job 8:20Bildad regards Job as a righteous man, who has fallen into sin.
God will not cast away a perfect man--(or godly man, such as Job was), if he will only repent. Those alone who persevere in sin God will not help (Hebrew, "take by the hand," Psa 73:23; Isa 41:13; Isa 42:6) when fallen.
job 8:21Till--literally, "to the point that"; God's blessing on thee, when repentant, will go on increasing to the point that, or until, &c.
job 8:22The haters of Job are the wicked. They shall be clothed with shame (Jer 3:25; Psa 35:26; Psa 109:29), at the failure of their hope that Job would utterly perish, and because they, instead of him, come to naught.