Again, I’m addressing Ammi’s rather stilted interpretation of the Scriptural text. Namely, that “lack of belief in the preaching one heard” → “condemnation”. That’s all I’m refuting – his interpretation runs counter not only to Church teaching, but also, to the witness of St Paul’s experience in Scripture
So, not having read all the comments, I am not sure what all has been said but according to Cornelius e Lapide’s great Catholic commentary on that bible passage he says this:
He that believeth … is not judged, shall not be condemned, but saved. But he that believeth not is judged, i.e., is condemned already.
For such an one manifestly condemns himself by his unbelief; for by it he cuts himself off from the very pathway and beginning of salvation, i.e., faith; because he hath not believed in the name…
This is the judgment, &c. (Vulg.) Judgment, i.e., cause of judgment, or condemnation. This is the cause why those are already condemned who believe not on Me, because they have preferred darkness, and ignorance of God, and of what they ought to do, and their own pleasures and lusts and sins upon the earth, rather than light, that is, Christ, who hath brought the knowledge of God and salvation into the world
And the Catholic Haydock commentary says:
Ver. 18. Is not judged. He that believeth, viz. by a faith working through charity, is not
judged; that is, is not
condemned; but the obstinate
unbeliever is
judged; that is,
condemned already, by retrenching (removing) himself from the society of Christ and his Church.
So, IMHO, one condemns himself when he chooses unbelief.