A Treatise on the Spirit and the Letter 26
26 No Fruit Good Except It Grow from the Root of Love PL 44, 217
It is evident, then, that the oldness of the letter, in the absence of the newness of the spirit, instead of freeing us from sin, rather makes us guilty by the knowledge of sin. Whence it is written in another part of Scripture, “He that increaseth knowledge, increaseth sorrow,”—not that the law is itself evil, but because the commandment has its good in the demonstration of the letter, not in the assistance of the spirit; and if this commandment is kept from the fear of punishment and not from the love of righteousness, it is servilely kept, not freely, and therefore it is not kept at all. For no fruit is good which does not grow from the root of love. If, however, that faith be present which worketh by love, then one begins to delight in the law of God after the inward man, and this delight is the gift of the spirit, not of the letter; even though there is another law in our members still warring against the law of the mind, until the old state is changed, and passes into that newness which increases from day to day in the inward man, whilst the grace of God is liberating us from the body of this death through Jesus Christ our Lord.
Apparet igitur litterae vetustatem, si desit novitas spiritus, reos facere potius cognitione peccati, quam liberare a peccato. Unde et alibi scriptum est, Qui apponit scientiam, apponit et dolorem : non quia ipsa lex malum est, sed quia mandatum bonum habet in littera demonstrante, non in adjuvante spiritu: quod mandatum si fit timore poenae, non amore justitiae, serviliter fit, non liberaliter, et ideo nec fit. Non enim fructus est bonus, qui de charitatis radice non surgit. Porro autem si adsit fides quae per dilectionem operatur , incipit condelectari legi Dei secundum interiorem hominem, quae delectatio non litterae, sed spiritus donum est; etiamsi alia lex in membris adhuc repugnat legi mentis, donec in novitatem, quae de die in diem in interiore homine augetur, tota vetustas mutata pertranseat, liberante nos de corpore mortis hujus gratia Dei per Jesum Christum Dominum nostrum.