The Lord Jesus Christ is the very Son of God, who has come down from heaven in the flesh to give His life as a ransom for many, and then from His Cross to preach the Gospel of the forgiveness of sins unto life and salvation. For by His Cross, and in His Resurrection from the dead, He has been given all authority in heaven and on earth, specifically for the sake of forgiving sinners like you, and thereby saving them, yourself included, from the devil, death, and hell.
Now, you would surely not question this authority of Jesus; leastwise not in theory! But you are kidding yourself if you claim to honor Him while you refuse to acknowledge and submit to His authority in the preaching, teaching, and ministry of those who are called and sent in His Name.
You pick and choose when and whether to heed and obey the Law that is preached to you. And too often you persist in your sins and fail even to confess them, instead of ceasing and desisting.
You also do not recognize your fundamental need for the external Word of the Gospel as it is preached by your pastors, administered in the Sacrament, and spoken in the Holy Absolution. You may or may not avail yourself of all these things. You can take it or leave it. And either way, you do what you do on your own terms, not in the humility of faith as a poor beggar before the Lord.
Oh, to be sure, you would readily affirm the authority of St. John the Baptist and his Baptism of repentance. But St. John is not here to confront you to your face concerning your own sins and moral failings. So that seems safe enough, while you presume to ignore his call to repentance.
Too many days come and go, in which you do not return to the significance of your Baptism into Christ Jesus. There is no contrition and repentance. Far less is there any righteousness and purity.
Yet, there is a man who has in fact been sent by God in heaven to call you to repentance. And it is therefore with the authority of the Lord Jesus Christ that I say to you, here and now in His Name:
Repent! Flee from your sin, from death and the devil, and return to your life in Christ.
Which is not to say that you are to pull yourself up by your own shoestrings, as though by trying harder you could clean up your act, keep your nose clean, and save yourself by some outward pretense of righteousness. By all means, discipline yourself and live as you should live. Cease and desist from doing what you know to be wrong, and begin to do what is good and right. Only do not suppose that you are thereby righteous in the sight of God, who knows your heart and mind. It is nothing else than your basic duty to keep His commandments, so do not expect any applause.
The call to repentance, however, is a call to give up your unbelief and to believe the Word of God.
Believe His Law, which exposes your sin and condemns you. Confess that you are a sinner, that you need to be saved, and that you cannot save yourself. Abandon all of your self-reliance.
Believe also the Gospel of God, whereby He forgives your sins and gives you life by giving you Christ Jesus, by laying Him upon your heart, mind, body, and soul with all His gifts and benefits.
It is by such repentance and faith that you acknowledge and submit yourself to the special authority of the Lord Jesus Christ. And in Him, by faith, you find that you have the very Savior that you need, who uses His authority not to condemn you but to save you by His grace.
He has submitted Himself to the Baptism of St. John, in order to fulfill all righteousness for you. So has He taken all your sins upon Himself, and suffered death and damnation in your stead, in order that His Resurrection from the dead should be your rescue and your righteousness in Him.
Thus, I say to you, by His authority: Your sins are all forgiven. You shall not die but live forever.
In the Name + of the Father and of the Son and of the Holy Spirit. Amen.