2. About him who has not Repented of a Past Mortal Sin

11. About the second I say that if his negligence is heavy and gross, because of which he does not recall his sin, he is not excused from sin, though he sins less than the first. The point is plain from I Corinthians 11.28, “Let a man,” he says, “prove himself etc.,” for he is bound to examine himself, with the diligence possible for our weakness, before he receives communion.

12. But if his negligence is not gross, as that sufficient examination has been done and no sin occurs to him about which he was not or is not contrite and has not confessed already, he does not sin by receiving communion, though perhaps something lies hidden or fallen into oblivion.

13. The proof is:

First that if, after such examination, he were to die contrite and confessed, he would be saved; but no greater examination is required for receiving communion than for dying in peace.

Second because otherwise anyone at all would be exposing himself to danger in receiving communion; for Psalm 18.13 says, “Who understands his sins?” and Ecclesiastes 9.1, “A man knows not whether he is worthy of love or hate.” Therefore, if it were necessary for someone who receives communion to be in a state of charity, anyone at all would expose himself to danger in receiving communion, since he does not know whether he would be sinning in doing that act.

The third proof is that then the sacrament would not be a sacrament for the wayfarer, since such certitude [sc. knowing one is in a state of grace or charity] does not belong to a wayfarer.

14. For this reason I say that when diligent examination has been done according to the possibility of our weakness, and when contrition has preceded, and confession has been made that, as it seems to man, is sufficient, then he does not sin if he then receives communion. On the contrary, if any sins remain hidden, they are remitted by the sacrament.