...we should recall that Paul did not write any evangelistic works. He addressed all his writing to Christians who already believed the gospel. He did not write to make converts, but to teach disciples who already believed. Each church had a different set of issues. Groups within churches had different issues. Whether the issues involved worship, doctrine, leadership, ethics, stewardship, spiritual gifts, marriage or anything else, Paul always rooted his teaching in the gospel. The gospel is not only the message of how to be saved, it is also the message of how to be saved. It is the message of both evangelism and discipleship. All Christian doctrine and practice have their basis in the gospel. Practices and beliefs of Christians that are not rooted in the gospel are not Christian. They may be cultural or personal, but all Christian belief and practice comes as an implication of the gospel.
Harry L. Poe
Recovering the Gospel for the Twenty-first Century
Southern Baptists, Evangelicals, and the Future of Denominationalism