Matthew 7:1-5: "Do not judge so that you will not be judged. For in the way you judge, you will be judged; and by your standard of measure, it will be measured to you. Why do you look at the speck that is in your brother's eye, but do not notice the log that is in your own eye? Or how can you say to your brother, 'Let me take the speck out of your eye,' and behold, the log is in your own eye? You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your brother's eye (emphasis mine)."
This is probably the most misused passage of the Bible. It is what critics of what is good and decent often use to defend themselves and their positions on homosexuality, abortion, living together before marriage, etc. "Don't judge!" is their mantra, while they fail to realize that they themselves are making a judgment when they make that exclamation. No judgment is allowed except the one judgment that judges that you are judging. This is akin to the relativist argument that there is no absolute truth except for the absolute truth that there is no absolute truth.
The condition necessary BEFORE making a judgment is to examine yourself, as is further explained in the following verses:
1 Corinthians 11:31: But if we judged ourselves rightly, we would not be judged.
2 Corinthians 13:5a: Test yourselves to see if you are in the faith; examine yourselves!
So, after we have examined ourselves, we are CALLED to make righteous judgments:
John 7:23-24: If a man receives circumcision on the Sabbath so that the Law of Moses will not be broken, are you angry with Me because I made an entire man well on the Sabbath? Do not judge according to appearance, but judge with righteous judgment (emphasis mine)."
Proverbs 31:9a: Open your mouth, judge righteously...
Here, Paul indicates having "judged" a believer caught in egregious sin:
1 Corinthians 5:1-5: It is actually reported that there is immorality among you, and immorality of such a kind as does not exist even among the Gentiles, that someone has his father's wife. You have become arrogant and have not mourned instead, so that the one who had done this deed would be removed from your midst. For I, on my part, though absent in body but present in spirit, have already judged him who has so committed this (emphasis mine), as though I were present. In the name of our Lord Jesus, when you are assembled, and I with you in spirit, with the power of our Lord Jesus, I have decided to deliver such a one to Satan for the destruction of his flesh, so that his spirit may be saved in the day of the Lord Jesus.
1 Corinthians 6:2-3: Or do you not know that the saints will judge the world (emphasis mine)? If the world is judged by you, are you not competent to constitute the smallest law courts? Do you not know that we will judge angels (emphasis mine)? How much more matters of this life?
If we will "judge the world"... and "angels", how much more are we to make RIGHTEOUS judgments in this life? Remember this next time someone tries to silence you by accusing you of "judging".