The Enchiridion by St. Augustine
Chapter 32.--The Freedom of the Will is Also the Gift of God, for God Worketh in Us Both to Will and to Do.
And further, should any one be inclined to boast, not indeed of his works, but of the freedom of his will, as if the first merit belonged to him, this very liberty of good action being given to him as a reward he had earned, let him listen to this same preacher of grace, when he says: |For it is God which worketh in you, both to will and to do of His own good pleasure;| and in another place: |So, then, it is not of him that willeth, nor of him that runneth, but of God that showeth mercy.| Now as, undoubtedly, if a man is of the age to use his reason, he cannot believe, hope, love, unless he will to do so, nor obtain the prize of the high calling of God unless he voluntarily run for it; in what sense is it |not of him that willeth, nor of him that runneth, but of God that showeth mercy,| except that, as it is written, |the preparation of the heart is from the Lord?| Otherwise, if it is said, |It is not of him that willeth, nor of him that runneth, but of God that showeth mercy,| because it is of both, that is, both of the will of man and of the mercy of God, so that we are to understand the saying, |It is not of him that willeth, nor of him that runneth, but of God that showeth mercy,| as if it meant the will of man alone is not sufficient, if the mercy of God go not with it, -- then it will follow that the mercy of God alone is not sufficient, if the will of man go not with it; and therefore, if we may rightly say, |it is not of man that willeth, but of God that showeth mercy,| because the will of man by itself is not enough, why may we not also rightly put it in the converse way: |It is not of God that showeth mercy, but of man that willeth,| because the mercy of God by itself does not suffice? Surely, if no Christian will dare to say this, |It is not of God that showeth mercy, but of man that willeth,| lest he should openly contradict the apostle, it follows that the true interpretation of the saying, |It is not of him that willeth, nor of him that runneth, but of God that showeth mercy,| is that the whole work belongs to God, who both makes the will of man righteous, and thus prepares it for assistance, and assists it when it is prepared. For the man's righteousness of will precedes many of God's gifts, but not all; and it must itself be included among those which it does not precede. We read in Holy Scripture, both that God's mercy |shall meet me,| and that His mercy |shall follow me.| It goes before the unwilling to make him willing; it follows the willing to make his will effectual. Why are we taught to pray for our enemies, who are plainly unwilling to lead a holy life, unless that God may work willingness in them? And why are we ourselves taught to ask that we may receive, unless that He who has created in us the wish, may Himself satisfy the wish? We pray, then, for our enemies, that the mercy of God may prevent them, as it has prevented us: we pray for ourselves that His mercy may follow us.