Sin is to a nature what blindness is to an eye. The blindness of an evil or defect which is a witness to the fact that the eye was created to see the light and, hence, the very lack of sight is the proof that the eye was meant... to be the one particularly capable of seeing the light. Were it not for this capacity, there would be no reason to think of blindness as a misforture.
So you see how endlessly futile and fruitless it would be if we wanted to refute their objections every time they obstinately resolved not to think through what they say but merely to speak, just so long as they contradict our arguments in any way they can.
The soul is "torn apart in a painful condition as long as it prefers the eternal because of its Truth but does not discard the temporal because of familiarity.
Now, justification in this life is given to us according to these three things: first by the laver of regeneration by which all sins are forgiven; then, by a struggle with the faults from whose guilt we have been absolved; the third, when our prayer is heard, in which we say: 'Forgive us our debts,' because however bravely we fight against our faults, we are men; but the grace of God so aids as we fight in this corruptible body that there is reason for His hearing us as we ask forgiveness.