John Calvin Commentary 1 Corinthians 3:18

"Let no man deceive himself. If any man thinketh that he is wise among you in this world, let him become a fool, that he may become wise." — 1 Corinthians 3:18 (ASV)

Let no man deceive himself. Here he identifies the core issue, as the whole problem originated in this: they were wise in their own conceit. Therefore, he exhorts them not to deceive themselves with a false impression by claiming any wisdom for themselves. By this, he means that all who depend on their own judgment are mistaken.

Now, in my opinion, he addresses both hearers and teachers. For the hearers showed a partiality for those ambitious men and listened to them, because they had too fastidious a taste, making the simplicity of the gospel insipid to them. Meanwhile, the teachers aimed at nothing but show, so that they might gain some esteem.

Accordingly, he admonishes both to this effect: “Let no one rest satisfied with his own wisdom, but let him who thinks himself to be wise, become a fool in this world.” Or, “Let him who is distinguished in this world by a reputation for wisdom, of his own accord empty himself, and become a fool in his own estimation.”

Furthermore, in these words the Apostle does not require us to altogether renounce the wisdom that is implanted in us by nature or acquired by long practice. Instead, he simply requires that we subject it to God’s service, so that we have no wisdom except through His word. For this is what is meant by becoming a fool in this world, or in our own estimation: when we are prepared to yield to God and embrace with fear and reverence everything that He teaches us, rather than follow what may seem plausible to us.

The meaning of the clause in this world is as if he had said, “According to the judgment or opinion of the world.” For the wisdom of the world is this: we consider ourselves self-sufficient for taking counsel in all matters (Psalms 13:2), for governing ourselves, and for managing whatever we have to do. It means we do not depend on any other. We feel no need for another’s guidance but believe we are competent to govern ourselves.

He, therefore, on the other hand, is a fool in this world who, renouncing his own understanding, allows himself to be directed by the Lord as if with his eyes shut. Such a person, distrusting himself, leans wholly on the Lord, places his entire wisdom in Him, and yields himself to God with docility and submission.

It is necessary for our wisdom to vanish in this way, so that God’s will may have authority over us, and for us to be emptied of our own understanding, so that we may be filled with God’s wisdom. At the same time, the clause “in this world” may either be connected with the first part of the verse or joined with the last. However, as the meaning is not significantly different, I leave it for each person to decide for himself.