But there is hardly anything more serious than to be joined in marriage to a stranger (i.e., to an unbeliever), where the instigations both of lustful appetite and of disharmony and the shameful crimes of sacrilege are welded together. For if marriage itself needs to be sanctified by the priestly veil and blessing, how is it possible to speak of a marriage where there is no agreement in faith?
Observe at the same time that the mystery consists in the very office of humility, for Christ says: 'If I, your Lord and Master, have washed your feet; how much more ought you to wash one another's feet.' For, since the Author of Salvation Himself redeemed us through His obedience, how much more ought we His servants to offer the service of our humility and obedience.
He therefore, the God Who rules over all things, must stretch out a saving hand to the wandering sheep, whom the Supreme Shepherd has now in fact redeemed. For He looked for it as it wandered afar, and He has placed it in a secure sheepfold, safe against thieves and wild beasts: namely, His Church.
The proof of authenticity of the spiritual condition of a father confessor is, that while he is very strict with himself, he is very lenient with others and does not use the canons of the Church like cannons against them.