Here quoting from a section in Luther’s sermon on John from 1532, pulled from Christian Freedom: Faith Working Through Love, A Readers Edition. Luther is condemning what he calls carnal liberty, or a freedom which proves to be license for the flesh to do as it desires, using the Gospel to sin. But true Christian freedom, and the want of all pious Christians, is to be set from our bondage and enslavement to sin. Only the Son sets us free, and we will be free indeed. Alleluia!
Note well that the real freedom is freedom from sin. Without this the temple at Jerusalem will not help you: neither will the pope with his whole train, whether it be indulgences, papal bulls, fasting, rosaries, prayers, or anything else. Neither Jews nor the pope will make us free; only the Son can do this. How does it come about? When we hear His Word-for instance, that Christ was born of Mary, suffered, was crucified, died, was buried, rose from the dead on the third day, etc. “Oh,” it is said, “I know all this very well! It is an old story. The pope, cardinals, and bishops are also familiar with it.” Indeed, they do know it. But learn this lesson of the children, for these words tell us how we are redeemed and set free. “Yes,” they say, “these sayings and words are so common that they do not do the work.” The children are to be highly commended for praying these words and also for understanding them sooner; for the more learned and the smarter we old fools claim to be, the less we know and understand about this subject.
To become free implies that you fix your thoughts on something else than that which lies in you, in the papacy, in the saints, or in Moses. You must direct your thoughts to something more exalted than all this, namely, the Son of God. Who is He? In the Creed we say: “Conceived of the Holy Spirit, born of Mary, died, etc.” Note well that you will really be pious and free from sin if you believe that Christ makes you free by dying for you, shedding His blood, rising from the dead, and sitting at the right hand of God.”
From Psalm 19:12-13
“Who can discern his errors?
Declare me innocent from hidden faults.
Keep back your servant also from presumptuous sins;
let them not have dominion over me!
Then I shall be blameless,
and innocent of great transgression.
Let the words of my mouth and the meditation of my heart
be acceptable in your sight,
O Lord, my rock and my redeemer.”