Therefore judge nothing before the time, until the Lord comes, who will both bring to light the hidden things of darkness and reveal the counsels of the hearts. Then each one’s praise will come from God.
In 1 Corinthians 4 the apostle Paul was pointing out the judgment that really counted. It wasn’t the opinions of the Corinthian congregation or of human courts or even Paul’s own judgment of himself (1 Corinthians 4:3-4).
The judgment that truly counts is God’s judgment of His people, which will be completed at Jesus Christ’s return. Then He will clearly judge our secret good deeds and sins and even our hidden motives—perhaps things we have hidden even from ourselves.
Paul’s point is not that God isn’t judging us now, because the Church is being judged now (1 Peter 4:17). And the point is not that we shouldn’t judge ourselves now, because Paul clearly says, “For if we would judge ourselves, we would not be judged” (1 Corinthians 11:31).
The point Paul was making was that we should not condemn others now. Not only can we not see the hidden things of their hearts, but we must remember that God is not finished with any of us yet.
For more about what the Bible says about judgment, see the article “What Did Jesus Mean by ‘Judge Not’?”