Most canonical laws rescind vows made before the age of fifteen; for before that age there does not seem sufficient judgment in a person to decide concerning a perpetual life.
Another Canon, granting more to the weakness of man, adds a few years; for it forbids a vow to be made before the age of eighteen.But which of these two Canons shall we follow? The most part have an excuse for leaving the monasteries, because most of them have taken the vows before they reached these ages.
Finally, even though the violation of a vow might be censured, yet it seems not forthwith to follow that the marriages of such persons must be dissolved.For Augustine denies that they ought to be dissolved (XXVII.Quaest.I, Cap.Nuptiarum), and his authority is not lightly to be esteemed, although other men afterwards thought otherwise.
But although it appears that God's command concerning marriage delivers very many from their vows, yet our teachers introduce also another argument concerning vows to show that they are void.For every service of God, ordained and chosen of men without the commandment of God to merit justification and grace, is wicked, as Christ says Matt.16, 9: In vain do they worship Me with the commandments of men.And Paul teaches everywhere that righteousness is not to be sought from our own observances and acts of worship, devised by men, but that it comes by faith to those who believe that they are received by God into grace for Christ's sake.
But it is evident that monks have taught that services of man's making satisfy for sins and merit grace and justification.What else is this than to detract from the glory of Christ and to obscure and deny the righteousness of faith? It follows, therefore, that the vows thus commonly taken have been wicked services, and, consequently, are void.
For a wicked vow, taken against the commandment of God, is not valid; for (as the Canon says) no vow ought to bind men to wickedness.