1 Corinthians 4:4

For I know nothing by myself, yet am I not hereby justified. I do not judge myself. For though I am not conscious of any unfaithfulness in my Apostolic office, yet I am not really just: I do not mean in the sight of men, for I do nor care for their judgment: I mean in the sight of God, who perhaps sees in me sins that I do not. Hence S. Basil (Constit. Monast. c. 1) says: " Although in many things we all offend, yet we have no conception at all of the greater part of our offences. This is why the Apostle once said, 'I know nothing by myself, yet am I not hereby justified.' It is as if he had said, 'I commit many venial sins of which I am bot aware.' For the same reason the prophet said, 'Who understands his offences?' You will not then be saying what is not true if you call yourself a sinner. "

From this we can argue against the Protestants that the justified have no sure knowledge, much less faith that they are justified. They reply that S. Paul means here that as regards his works he did not know that he was justified, but that he had a sure knowledge of it from faith and Holy Scripture, which promise justification to every one that believeth on Christ. In other words, they say that they know that they are justified, not because they are free from sins, and live holy lives, but through God's mercy accepting their belief in the free gift of justification by Christ. But this answer of theirs is frivolous and feigned, for the Apostle goes on to say,