"The concern in this chapter is with the extent to which Paul's gospel is the same as, or represents a radical departure from, that of the Gospel writers and the other apostles."
Gathercole identifies three central aspects of the gospel message---"the core of the euangelion according to Paul"---found in the Pauline epistles:
(1) who Jesus is, with particular reference to his identity as royal Messiah and son of God;
(2) his work of atonement and justification accomplished in the cross and resurrection, and
(3) Jesus' work of new creation and of rescue from the power of sin.
The gospel according to Paul, Gathercole writes, "is simultaneously an affirmation of who Jesus is as well as of what he has done." Gathercole defines the gospel in the Paul materials as "God's account of his saving activity in Jesus the Messiah, in which, by Jesus' death and resurrection, he atones for sin and brings new creation."
He then turns to the synoptic material and works through these three themes of
(2) Jesus' death for the many
(3) The conquest of the demonic realm and the reign of God
You can read the whole thing here.