10 The first stage of liberty, then, is to be free from crimes [sinful conduct]. And so the Apostle Paul, when he determined on the ordination of either elders or deacons, or whoever was to be ordained to the superintendence of the Church, says not, If any one is without sin; for had he said so, every one would be rejected as unfit, none would be ordained: but he says, “If any one is without crime” [E.V. blame], such as, murder, adultery, any uncleanness of fornication, theft, fraud, sacrilege, and others of that sort.
When a man has begun to be free from these (and every Christian man ought to be so), he begins to raise his head to liberty; but that is liberty begun, not completed. Why, says some one, is it not completed liberty? Because, “I see another law in my members warring against the law of my mind;” “for what I would,” he says, “that do I not; but what I hate, that do I.” “The flesh,” he says, “lusts against the spirit, and the spirit against the flesh; so that you do not the things that you would.” In part liberty, in part bondage: not yet entire, not yet pure, not yet full liberty, because not yet eternity.
For we have still infirmity in part, in part we have attained to liberty. Whatever has been our sin, was previously wiped out in baptism. But because all our iniquity has been blotted out, has there remained no infirmity? If there had not, we should be living here without sin. Yet who would venture to say so, but the proud, but the man unworthy of the Deliverer's mercy, but he who wishes to be self-deceived, and who is destitute of the truth? Hence, from the fact that some infirmity remains, I venture to say that, in what measure we serve God, we are free; in what measure we serve the law of sin, we are still in bondage.
Hence says the apostle, what we began to say, “I delight in the law of God after the inward man.” Here then it is, wherein we are free, wherein we delight in the law of God; for liberty has joy. For as long as it is from fear that you do what is right, God is no delight to you. Find your delight in Him, and you are free. Fear not punishment, but love righteousness. Are you not yet able to love righteousness? Fear even punishment, that you may attain to the love of righteousness.
Source: Tractates on the Gospel of John (New Advent)