While each Epistle has several purposes, there is often a main purpose that strikes the reader. Galatians was intended to address issues around Gentiles being part of the Church; 2 Thessalonians addresses eschatological doctrine; 1 Corinthians addresses chaos, morality, and discipline in church conduct and governance. We could say that the predominant purpose of Romans is to preach the Gospel and hand it on for posterity.
Romans is a long epistle and the Gospel portion of it is lengthy. This may seem odd to modern Christians who may be used to condensed versions of the Gospel along the lines of “Jesus died in our place so that our sins could be forgiven.” I hasten to add that I am not opposed to shortened versions of the Gospel where appropriate, but do point out that frequently in Acts the Gospel is preached in a narrative format, just as Paul chooses to in Romans.
Paul’s Gospel is international and rooted in the Jewish Scriptures, which he presents as a record of oracles, covenants, and promises made by God to His people Israel. Paul depicts Christ as Jewish and human, thus both particular and universal. He also presents Him as man and God: both perfect and able to identify with us in our plight. Paul’s Jesus is the Saviour, the One who fulfils God’s promises to Israel and delivers us from darkness and the wrath of God.
Paul makes clear from the beginning that this salvation is a gift from God, not merited by our works and to be received by coming to God and trusting Him, forsaking former religious ties, and holding on for the end, though we do not see God with our eyes in this life.
Paul tells the story of our descent into darkness, which simultaneously reveals both our need for salvation and the fate of those who will not repent. He illustrates our spiritual darkness with examples, ranging from polytheism and idolatry, which would have been familiar to the Roman’s, littered and Rome was with temples and statues, to sexual misconduct and general disobedience and selfishness.
Here Paul’s theology moves on to two points: God’s temporary abandonment of the Gentiles (Deuteronomy 32 and Psalm 82); and the fact that God does not force salvation on anyone: we must freely accept the Gospel.
This allows Paul to set up the election and purpose of Israel, which is an essential element of his Gospel narrative. Paul also begins warning that sin leads to death: there is something from which we are to be saved as well as Someone we are to be saved for.