"If we just preach general doctrine and ethics from Scripture, we are not preaching the gospel. The gospel is the good news that God has accomplished our salvation for us through Christ in order to bring us into a right relationship with him and eventually to destroy all the results of sin in the world. Still, it can be rightly argued that in order to understand all this -- who God is, why we need salvation, what he has done to save us -- we must have knowledge of the basic teachings of the entire Bible. J. Gresham Machen, for example, speaks of the biblical doctrines of God and of man to be the "presuppositions of the gospel."10 This means that an understanding of the Trinity, of Christ's incarnation, of original sin and sin in general -- are all necessary. If we don't understand, for example, that Jesus was not just a good man but the second person of the Trinity, or if we don't understand what the "wrath of God" means, it is impossible to understand what Jesus accomplished on the cross. Not only that, but the New Testament constantly explains the work of Christ in Old Testament terms -- in the language of priesthood, sacrifice, and covenant. In other words, we must not just preach the Bible in general; we must preach the gospel. Yet unless those listening to the message understand the Bible in general, they won't grasp the gospel. The more we understand the whole corpus of biblical doctrine, the more we will understand the gospel itself -- and the more we understand the gospel, the more we will come to see that this is, in the end, what the Bible is really about."