Anti-pelagian Writings by St. Augustine
Chapter 26.--No Fruit Good Except It Grow from the Root of Love.
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.