As I already said in A few quotes from The Theology of St. Luke by Hans Conzelmann (Part 1), Conzelmann has not taken any interest in this book in harmonizing Luke with Paul’s theology nor his own theology but rather simply in describing Luke’s theology as he understands it from Luke-Acts.
Because he proceeds in this way, he even takes notice in some places of the fact that Luke and Paul do not agree with each other. Another example of this is on page 228:
The conception of sin [in Luke-Acts], compared with Paul’s, has a strong ethical colouring, and the same is true of deliverance from sin. The idea of ‘forgiveness’, which recedes right into the background in Paul, is predominant in Luke, but repentance is the condition of forgiveness.
My elaboration: Unlike Paul who speaks of justification instead of forgiveness and all but denies the necessity of repentance to ‘justification’. Luke’s theology which emphasizes forgiveness of sins on the basis of repentance clearly calls for repentance, whereas Paul’s justification by faith and not by works deters people from repenting by making them feel that they are justified in continuing to sin even with reckless abandon.
Forgiveness and repentance [in Luke-Acts] are inseparably connected…The combination which is characteristic of Luke is that of repentance and conversion, which shows that these two go together as the basis for Baptism and forgiveness and indicate a change of attitude in the way of life.
How very different from Paul! And that is precisely the point.