1 Corinthians 3:1-4, 18-20

But I, brothers, could not address you as spiritual people, but as people of the flesh, as infants in Christ. I fed you with milk, not solid food, for you were not ready for it. And even now you are not yet ready, for you are still of the flesh. For while there is jealousy and strife among you, are you not of the flesh and behaving only in a human way? For when one says, “I follow Paul,” and another, “I follow Apollos,” are you not being merely human?

Let no one deceive himself. If anyone among you thinks that he is wise in this age, let him become a fool that he may become wise. For the wisdom of this world is folly with God. For it is written, “He catches the wise in their craftiness,” and again, “The Lord knows the thoughts of the wise, that they are futile.”