1 Corinthians 6:2

2.Know ye not that the saints. Here we have an argument from the less to the greater; for Paul, being desirous to show that injury is done to the Church of God when judgments on matters of dispute connected with earthly things are carried before unbelievers, as if there were no one in the society of the godly that was qualified to judge, reasons in this strain: “Since God has reckoned the saints worthy of such honor, as to have appointed them to be judges of the whole world, it is unreasonable that they should be shut out from judging as to small matters, as persons not qualified for it.” Hence it follows, that the Corinthians inflict injury upon themselves, in resigning into the hands of unbelievers the honor (318) that has been conferred upon them by God.

What is said here as to judging the world ought to be viewed as referring to that declaration of Christ:

When the Son of Man shall come, ye shall sit, etc.
(Matthew 19:28.)

For all power of judgment has been committed to the Son,
(John 5:22,)

in such a manner that he will receive his saints into a participation with him in this honor, as assessors. Apart from this, they will judge the world, as indeed they begin already to do, because their piety, faith, fear of the Lord, good conscience, and integrity of life, will make unbelievers altogether inexcusable, as it is said of Noah, that by his faith he condemned all the men of his age. (Hebrews 11:7.) But the former signification accords better with the Apostle’s design, for unless you take the judging here spoken of in its proper acceptation, the reasoning will not hold.

But even in this sense (319) it may seem not to have much weight, for it is as if one should say’ “The saints are endowed with heavenly wisdom, which immeasurably transcends all human doctrines: therefore they can judge better as to the stars than astrologers.” Now this no one will allow, and the ground of objection is obvious — because piety and spiritual doctrine do not confer a knowledge of human arts. My answer here is this, that between expertness in judging and other arts there is this difference, that while the latter are acquired by acuteness of intellect and by study, and are learned from masters, (320) the former depends rather on equity and conscientiousness.

But (321) “lawyers will judge better and more confidently than an illiterate Christian: otherwise the knowledge of law is of no advantage.” I answer, that their advice is not here excluded, for if the determination of any obscure question is to be sought from a knowledge of the laws, the Apostle does not hinder Christians from applying to lawyers. (322) What he finds fault with in the Corinthians is simply this, that they carry their disputes before unbelieving judges, as if they had none in the Church that were qualified to pass judgment, and farther, he shows how much superior is the judgment that God has assigned to his believing people.

The words rendered in you mean here, in my opinion, among you. For whenever believers meet in one place, under the auspices of Christ, (323) there is already in their assembly a sort of image of the future judgment, which will be perfectly brought to light on the last day. Accordingly Paul says, that the world is judged in the Church, because there Christ’s tribunal is erected, from which he exercises his authority. (324)