As the clean and purified spirit can find rest only in God, having been created for this end, so there is no place save Hell for the soul in sin, for whose end Hell was ordained by God. When the soul as it leaves the body is in mortal sin, then, in the instant in which spirit and body are separated, the soul goes to the place ordained for it, unguided save by the nature of its sin. And if at that moment the soul were bound by no ordinance proceeding from God's justice, it would go to a yet greater hell than that in which it abides, for it would be outside His ordinance, in which divine mercy has part so that God gives the soul less pain than it deserves. The soul, finding no other place to hand nor any holding less evil for it, casts itself by God's ordinance into Hell as into its proper place.
To return to our matter which is the Purgatory of the soul separated from the body when it is no longer clean as it was created. Seeing in itself the impediment which can be taken away only by means of Purgatory, it casts itself therein swiftly and willingly. Were there not the ordinance it thus obeys, one fit to rid it of its encumbrance, it would in that instant beget within itself a hell worse than Purgatory, for it would see that because of that impediment it could not draw near to God, its end. So much does God import that Purgatory in comparison counts not at all, for all that it is, as has been said, like Hell. But compared to God, it appears almost nothing.