St. John the Baptist spoke of works worthy of repentance.
Lutherans, technically, reject the idea of penance. Now if you ask us, "Should a thief return what they stole?" The answer is DUH, of course they should. But that has nothing to do with God's forgiveness when we come before Him confessing our sins, penitent. Rather that's just common sense, of course you should do that. Making amends with those we have injured isn't a penance we do, but is instead just what we should do.
And, further, we are to seek to live our lives with good works, good works "worthy of repentance". Because the penitent heart, broken by grief over sin, and healed by the grace of God's mercy, desires to do good works. For faith produces good works.
This is part of our Law-Gospel Dialectic. That the Law is the Law, the Gospel is the Gospel, and we don't confuse them. So that means making a sharp distinction between righteousness before God (Justification, Gospel, righteousness received through faith alone), and righteousness before the world (Sanctification, Law, righteousness done because it is good and right to be done for the sake of our neighbor).
If I steal and return what is stolen, God does not count this as righteousness before Him--I shouldn't have stolen in the first place. But it is an act of restitution toward my neighbor who I have injured.
-CryptoLutheran