It was ironically in a 1 Corinthians commentary, that I found this gem of a quote about Paul, apocalypticism, and salvation-history in Romans. Roy E. Ciampa and Brian S. Rosner (The First Letter to the Corinthians [PNTC; Grand Rapids, MI: Eerdmans, 2010], 10) write:
The salvation-historical and apocalyptic perspectives are not, for Paul, two irreconcilable outlooks standing in unresolved tension. Instead, the two perspectives converge in Paul’s thought such that he regards the history of the particular nation of Israel as finding its fulfillment, through Jesus Christ, in salvation for the entire world. The convergence of salvation-historical and apocalyptic motifs is nowhere more apparent than in the two ‘bookends’ to Romans 1:1-5 and 16:25-27. The gospel of Jesus Christ, descended from David according to the flesh yet declared to be the Son of God in power according to the Spirit of holiness by his resurrection from the dead, has cosmic significance. This ‘mystery’ was kept secret for long ages but has now been disclosed and through the prophetic writings (i.e., the historical Scriptures of Israel) has been made know to all the nations, and must be proclaimed to the world and its authorities. It is the eschatological ‘power of God for salvation’ (Rom. 1:16). Paul the regards himself as a herald who has been commissioned by Jesus to perform this task. Paul has been sent, through a special revelation of God’s Son, to preach to the Gentiles (Gal. 1:11, 16). He is one of two ‘point men’ in God’s eschatological mission, having been entrusted with the gospel to the Gentiles just as Peter was entrusted with the gospel to the Jews (Gal.2:7).