I myself am satisfied about you, my brothers, that you yourselves are full of goodness, filled with all knowledge and able to instruct one another.
Paul wrote these confident words to a church filled with Christians he had never met. In fact, the rest of Romans 15 details his hopeful plans for traveling to Rome to visit them for the first time. There were evidently some people there who knew Paul, the apostle to the Gentiles, but the book of Romans was meant to be Paul's first preaching of the gospel to them.
Even though Paul had never set foot in a meeting of this church, he was confident that three things marked the fellowship there already: goodness, knowledge, and competent caring instruction. These three marks of church health are still to be found in solid New Testament, gospel-centered churches even today. They are worth contemplating as much now as when Paul commended these characteristics to the church in Rome.
First, New Testament churches are full of goodness. The good works that result from the change toward holiness affected by our salvation and the focus of the gospel on God saving us in Christ will show fruit in what we do. God's holiness will be demonstrated to the world. As Jesus commanded, so we live, so that men may see our good works and glorify God.
Secondly, New Testament churches have spiritual knowledge. The gospel is the truth about salvation and Jesus Christ. The Word of God preached is the saturating influence on all we do or believe in the church. That knowledge changes us, even as it shapes our theology and our consistent message over the history of the church... at this point through multiple cultures around the world and across two millennia of world history.
Finally, biblical churches have members skilled in admonishing, helping, and instructing each other. This is much more than mere teaching. It involves directive care to apply the goodness and knowledge that marks the church to the real lives of the disciples in her midst. It is counsel and care that is the staple of any ministry of biblical counseling, as well as the outworking of church-based discipleship. It is disciple-making disciplemakers making disciples in the context of real life.