6 But that which follows, “And when He has come, He will convince the world of sin, and of righteousness, and of judgment: of sin, indeed, because they believe not on me; but of righteousness, because I go to the Father, and you shall see me no more; and of judgment, because the prince of this world is judged”; as if it were sin simply not to believe in Christ; and as if it were very righteousness not to see Christ; and as if that were the very judgment, that the prince of this world, that is, the devil, is judged: all this is very obscure, and cannot be included in the present discourse, lest brevity only increase the obscurity; but must rather be deferred till another occasion for such explanation as the Lord may enable us to give.
Source: Tractates on the Gospel of John (New Advent)