In my Sunday school class, the teacher explained that unlike many of his epistles were to known contacts he knew, but this epistle was to a congregation he did not personally know.
That point made me realize Rome was the most cosmopolitan city of this day. The congregation would likely have been like many of the major city congregations I have worshiped with. They are almost always very diverse groups; it is a mixture of rich and poor, and come from many countries.
One of the major topic is the law that many of the converts from Judaism. This passage from Bruce R. McConkie’s “Doctrinal New Testament Commentary” about Romans Chapter 5 is helpful in explaining much of the content in Paul’s early writings, including Romans, 1 and 2 Corinthians, and Galatians.
“Paul’s presentation here is obscure and difficult…
“Something, however, should be said in mitigation of the obscurity and ambiguity of the argument Paul makes. The fact is that the philosophical problems facing his Roman readers were wholly different from those with which we wrestle today. We do not have the Mosaic background, and are not concerned with how the law of Moses died in Christ; we are not confronted with the problem of rationalizing away those performance which had been drilled into Israel for fifteen hundred years; we are not faced with the problem of showing that the gospel grew out of the Mosaic order….
“Nonetheless, Paul’s argument, given of old, does have worth and merit for us; it enables us to get an over-all view of God’s dealings with men; it helps us understand better what we do have in the revealed religion which has come to us. In effect Paul is saying that the law of Moses was good in its day, that God gave it for a purpose, but that now it is dead, and in place thereof God had given a higher law to which all men must now turn for salvation.”