Chapter 2 is necessary for Systematic Theology. To help understand, when this was written, there were very few Christians. Also, at the time of the writing, there is not much of a concept of what a Christian was. However, at the time of the writing there were millions of Jews. Although Christianly is built on the Jewish faith, Paul has to explain in Rom.2:1-27 that Jews and non-Jews all need Jesus. This explanation culminates with verses 28 and 29.