Augustine of Hippo — as excerpted in the Catena Aurea on John 8:31-36

“O miserable bondage! The slave of a human master when wearied with the hardness of his tasks, sometimes takes refuge in flight. But whither does the slave of sin flee? He takes it along with him, wherever he goes; for his sin is within him. The pleasure passes away, but the sin does not pass away: its delight goes, its sting remains behind. He alone can free from sin, who came without sin, and was made a sacrifice for sin. And thus it follows: The servant abideth not in the house for ever. The Church is the house: the servant is the sinner; and many sinners enter into the Church. So He does not say, The servant is, not in the house; but, The servant abideth not in the house for ever. If a time then is to come, when there shall be no servant in the house; who will there be there? Who will boast that he is pure from sin? Christ’s are fearful words. But He adds, The Son abideth for ever. So then Christ will live alone in His house. Or does not the word Son, imply both the body and the head? Christ purposely alarms us first, and then gives us hope. He alarms us, that we may not love sin; He gives us hope, that we may not despair of the absolution of our sin. Our hope then is this, that we shall be freed by Him who is free. He hath paid the price for us, not in money, but in His own blood: If the Son therefore shall make you free, ye shall be free indeed.”