Job 9:4

He is wise in heart, and mighty in strength - By his infinite knowledge he searches out and sees all things, and by his almighty power he can punish all delinquencies. He that rebels against him must be destroyed.

He is wise in heart - Herder renders this,

Even the wise and the powerful,

Who hath withstood him and prospered?

But the more common interpretation is to refer it to God. The meaning of Job appears to be, that God was a sagacious adversary; that he was able to manage his cause; that he could meet and refute all objections which could be urged; and that it would be in vain to engage in a litigation before him. He so well understood the whole ground of debate, and was so entirely skilled in the merits of the controversy, and could so successfully meet all that could be alleged, that it was useless to attempt to hold an argument with him.

And mighty in strength - He is able to execute all his designs, and to carry all his purposes into effect. Man is weak and feeble, and it is hopeless for him to attempt to contend with the Almighty.

Who hath hardened himself against him, and hath prospered? - To harden oneself, here means to resist or withstand him. It refers to the firmness or resolution which one is obliged to adopt who opposes another. Here it means the opposition which man makes to the law and government of the Most High; and the affirmation is, that no one can make such opposition who will not be ultimately overcome. God is so great, so powerful, and so just, that a successful resistance cannot be made. The arrangements of God will take their course, and man must yield to his claims and his government, or be prostrated. None can successfully resist God; and the true policy of man, as well as his duty, is to yield to him, and be at peace with him.

And hath prospered - Or been successful. He has failed in his opposition, and been obliged to yield. Prosperity is not found in opposing God. It is only by falling in with his arrangements and following his designs. A prosperous voyage is made by falling in with winds and currents, and not in opposing them; prosperous agriculture is carried on by coinciding with the favorable seasons of the year, and taking advantage of the dews, and rains, and sunbeams that God sends, and not in opposing them; prosperity in regard to health is found in taking advantage of the means which God gives to secure it, and not in opposing them. And the sinner in his course has no more chance of success and prosperity, than a man would have who should make it a point or principle of life always to sail against tides, and currents, and head winds; or he who should set at defiance all the laws of husbandry, and plant on a rock, or in the dead of winter; or he who should feed himself on poison rather than on nutritious food, and cultivate the nightshade rather that wheat. The great principle is, that if a man desires prosperity, he must fall in with the arrangements of God in his providence and grace; and wisdom is seen in studying these arrangements, and in yielding to them.

9:4 He - He is infinitely wise, and searcheth all mens hearts and ways, and discovers a multitude of sins which mens short sighted - eyes cannot see; and therefore can charge them with innumerable evils, where they thought themselves innocent, and sees far more malignity than men could discern in their sins. Mighty - So that whether men contend with God by wisdom or by strength: God will be conqueror.Hardened himself - Obstinately contended with him. The devil promised himself that Job in the day of his affliction, would curse and speak ill of God. But instead of that, he sets himself to honour God, and speak highly of him. As ill pained as he is, and as much as he is taken up with his own miseries, when he has occasion to mention the wisdom and power of God, he forgets his complaints and expatiates with a flood of eloquence on that glorious subject.