| Barnes' Notes on the Bible Which doeth great things - This is almost the sentiment which had been expressed by Eliphaz; see the notes, Job 5:9. It was evidently a proverb, and as such was used by both Eliphaz and Job.
Clarke's Commentary on the BibleGreat things past finding out - Great things without end; wonders without number - Targum.
Gill's Exposition of the Entire BibleWhich doth great things past finding out,.... In heaven and earth; great as to quantity and quality, not to be thoroughly searched out so as to tell their numbers, nor explain and express the nature of them to the full; even what he has done, and does in creation, providence, and grace: yea, and wonders without number; such as are amazing to men, who cannot account for them, and so many that they cannot number them. The same things are said by Eliphaz; see Gill on Job 5:9; and which Job here repeats, to show that he agreed with him, and was ready to own what was truth, whenever expressed by him or his friends, and especially such as made for the glory of the Divine Being.
Geneva Study BibleWhich doeth great things past finding out; yea, and wonders without number.
Wesley's Notes 9:10 Doth great things, and c. - Job here says the same that Eliphaz had said, chap.5:9, and in the original, in the very same words, with design to shew his full agreement with him, touching the Divine perfections.
Jamieson-Fausset-Brown Bible Commentary10. Repeated from Eliphaz (Job 5:9).
Matthew Henry's Concise Commentary9:1-13 In this answer Job declared that he did not doubt the justice of God, when he denied himself to be a hypocrite; for how should man be just with God? Before him he pleaded guilty of sins more than could be counted; and if God should contend with him in judgment, he could not justify one out of a thousand, of all the thoughts, words, and actions of his life; therefore he deserved worse than all his present sufferings. When Job mentions the wisdom and power of God, he forgets his complaints. We are unfit to judge of God's proceedings, because we know not what he does, or what he designs. God acts with power which no creature can resist. Those who think they have strength enough to help others, will not be able to help themselves against it. | 
