Justification: Jesus --> Paul

The last sentence of Richard Gaffin's fascinating article "Justification in Luke-Acts," in Right with God, edited by D. A. Carson, is:

The gospel of justification by faith advocated by Paul is the fruition, the doctrinally more explicit and developed delineation, of the good news of repentance for the forgiveness of sins which was announced by Jesus, and which, more importantly, was actualised in his death, resurrection, ascension, and baptism with the Holy Spirit. (p. 125)