12 “For God sent not His Son into the world to judge the world, but that the world through Him may be saved.” So far, then, as it lies in the physician, He has come to heal the sick. He that will not observe the orders of the physician destroys himself. He has come a Saviour to the world: why is he called the Saviour of the world, but that He has come to save the world, not to judge the world? You will not be saved by Him; you shall be judged of yourself. And why do I say, “shall be judged”? See what He says: “He that believes in Him is not judged, but he that believes not.” What do you expect He is going to say, but “is judged”? “Already,” says He, “has been judged.” The judgment has not yet appeared, but already it has taken place. For the Lord knows them that are His: He knows who are persevering for the crown, and who for the flame; knows the wheat on His threshing-floor, and knows the chaff; knows the good grain, and knows the tares. He that believes not is already judged. Why judged? “Because he has not believed in the name of the only-begotten Son of God.”
Source: Tractates on the Gospel of John (New Advent)