For each individual lives by his own faith, nor is there exception of persons with God; since it is not hearers of the law who are justified by the Lord, but doers, according to what the apostle withal says. Therefore, if you have the right of a priest in your own person, in cases of necessity, it behoves you to have likewise the discipline of a priest whenever it may be necessary to have the fight of a priest.
Source: On Exhortation to Chastity