Then he opened their minds to understand the Scriptures, and said to them, “Thus it is written, that the Christ should suffer and on the third day rise from the dead, and that repentance for the forgiveness of sins should be proclaimed in his name to all nations… -Luke 24:45-47
What is repentance in His name? Hereby he singles out the repentance that is not made in His name, and therefore the text compels us to consider two kinds of repentance. First, a repentance not in His name is, when I come with my own works and undertake to blot out sin with them; as we all have been taught and have tried to do. This is not repentance in God’s name, but in the devil’s name. For this is striving to propitiate God by our own works and by our own strength, a thing God cannot allow.
But on the other hand, to repent in His name is done thus: in those who believe in Christ God through the same faith works a change for the better, not for a moment, nor for an hour, but for their whole life. For a Christian is not instantaneously or suddenly cleansed perfectly, but the reformation and change continue as long as he lives. Though we use the utmost diligence, we will always find something to sweep or clean. For even though all wickedness be overcome, we have not yet overcome the fear of death, for few have come so far as to desire death with a spirit of rejoicing; hence, we must grow better day by day. This is what Paul means, when he says in 2 Corinthians 4:16: “Though our outward man is decaying, yet our inward man is renewed day by day.” For we hear the Gospel every day, and Christ shows us His hands and His feet every day that our minds may be still more enlightened, and we be made more and more godly.
For this reason, Christ would say, let no one strive to amend his life by his own works and in his own name; for of themselves no one is an enemy of sin, no one will come to repentance and think of amending his life. Nothing will be accomplished except in my name. That name alone has power to do it, and brings with it willingness and desire to be changed. But if the works and doctrines of men be taught, I will go and say to myself: O, that I might not need to pray, nor make confession, nor go to the Lord’s Supper! What will your repentance profit you, if you fail to do it gladly or willingly, but are constrained by the commandment or by fear of shame, otherwise you would rather not do it? But what is the reason? Because it is a repentance in the devil’s name or in your own name. Hence you go on and do worse things, and wish there were no confession and sacrament, so that you might not be constrained to attend them. This is repentance in our own name, and proceeds from our own strength.
But when I begin to believe in Christ, lay hold of the Gospel, and do not doubt that he has taken away my sin and blotted it out, and comforts me with his resurrection; my heart is filled with such gladness that I myself take hold willingly, not through persuasion, nor of necessity, I gladly do what I ought and say: Because my Lord has done this for me, I will also do his will in this, that I may amend my ways and repent out of love to him and to his glory. In this way, a true reformation begins that proceeds from the innermost heart, and that is brought forth by the joy that flows from faith, when I apprehend the greatness of the love Christ has bestowed upon me.
[This is an excerpt from a sermon preached by Martin Luther]