Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Job 21:1-6) Job entreats attention.
(Job 21:7-16) The prosperity of the wicked.
(Job 21:17-26) The dealings of God's providence.
(Job 21:27-34) The judgement of the wicked is in the world to come.
Job comes closer to the question in dispute. This was, Whether outward prosperity is a mark of the true church, and the true members of it, so that ruin of a man's prosperity proves him a hypocrite? This they asserted, but Job denied. If they looked upon him, they might see misery enough to demand compassion, and their bold interpretations of this mysterious providence should be turned into silent wonder.
Job says, Remarkable judgments are sometimes brought upon notorious sinners, but not always. Wherefore is it so? This is the day of God's patience; and, in some way or other, he makes use of the prosperity of the wicked to serve his own counsels, while it ripens them for ruin; but the chief reason is, because he will make it appear there is another world. These prospering sinners make light of God and religion, as if because they have so much of this world, they had no need to look after another. But religion is not a vain thing. If it be so to us, we may thank ourselves for resting on the outside of it. Job shows their folly.
Job had described the prosperity of wicked people; in these verses he opposes this to what his friends had maintained about their certain ruin in this life. He reconciles this to the holiness and justice of God. Even while they prosper thus, they are light and worthless, of no account with God, or with wise men. In the height of their pomp and power, there is but a step between them and ruin. Job refers the difference Providence makes between one wicked man and another, into the wisdom of God. He is Judge of all the earth, and he will do right. So vast is the disproportion between time and eternity, that if hell be the lot of every sinner at last, it makes little difference if one goes singing thither, and another sighing. If one wicked man die in a palace, and another in a dungeon, the worm that dies not, and the fire that is not quenched, will be the same to them. Thus differences in this world are not worth perplexing ourselves about.
Job opposes the opinion of his friends, That the wicked are sure to fall into visible and remarkable ruin, and none but the wicked; upon which principle they condemned Job as wicked. Turn to whom you will, you will find that the punishment of sinners is designed more for the other world than for this, Jde 1:14, Jde 1:15. The sinner is here supposed to live in a great deal of power. The sinner shall have a splendid funeral: a poor thing for any man to be proud of the prospect of. He shall have a stately monument. And a valley with springs of water to keep the turf green, was accounted an honourable burial place among eastern people; but such things are vain distinctions. Death closes his prosperity. It is but a poor encouragement to die, that others have died before us. That which makes a man die with true courage, is, with faith to remember that Jesus Christ died and was laid in the grave, not only before us, but for us. That He hath gone before us, and died for us, who is alive and liveth for us, is true consolation in the hour of death.