For the flesh lusts against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that you cannot do the things that you would.
All Commentaries on Galatians 5:17 Go To Galatians 5
Augustine of Hippo
AD 430
People think that the apostle here denies that we possess free will. They do not perceive what he is saying to them: If they refuse to hold fast to the grace they have received, through which alone they are able to walk in the Spirit and avoid fulfilling the desires of the flesh, they will not be able to do as they wish…. It is love that “fulfills the law.” But “the wisdom of the flesh” by following temporal goods opposes spiritual love. How can it be made subject to the law of God (that is, freely and obediently fulfill righteousness and not be opposed to it) when even as it tries it must be vanquished? The flesh imagines that it can procure a greater temporal good by iniquity than by maintaining righteousness. The first stage, the natural life of a human being, precedes the law, when no wrongdoing or malice is prohibited. The natural being makes no resistance at all to base desires, since there is no one to prohibit them. The second stage is under law before grace, when he is indeed prohibited and tries to abstain from sin but is overcome because he does not yet love righteousness for God’s sake and its own but wishes to observe it in the hope of earthly acquisitions. And therefore, when he sees righteousness on one side and temporal good on another, he is dragged by the weight of his temporal desire and thus forsakes righteousness, which he was trying to maintain only in order to have that which he now sees that he is going to lose by maintaining it. The third stage of life is the one under grace, when no temporal good is preferred to righteousness. This cannot happen except by spiritual love, which the Lord has taught by his example and bestowed by grace. For in this life, even if there remain desires of the flesh from the mortality of the body, yet they do not subdue the mind to consent to sin.