“Then you will know the truth, and the truth will set you free”
“A slave does not remain in a household forever.” That household is the Church and the slave is the sinner. Great numbers of sinners enter the Church. So the Lord does not say that the slave “is not” but that he “does not remain” in the household forever… When the king over all justice is seated on his throne, as Scripture says (Mt 25:31), which of us will be able to boast of having a pure heart? Who will be able to boast of not having been soiled by sin?… What hope do we have, then, we who are not without sin?
Listen to your hope: "But a Son always remains. So if a Son frees you, then you will be truly free"… For we were the servants of our own egotism; but being set free, we will become servants of love. This is what the apostle Paul says: "For you were called for freedom, brothers. But do not use this freedom as an opportunity for the flesh; rather, serve one another through love" (Gal 5:13). A Christian cannot say: “I am free; I have been called to liberty: I used to be a slave but have been redeemed, and by my very redemption have been made free, I shall do what I please: let no one stand against my will; I am free!” No, if you commit sin with such a will, you become a servant of sin. Do not abuse your liberty… but use it for the purpose of avoiding sin. You will be free if you become a servant, freed from sin if you become a servant of righteousness.