The New Testament epistles were, of course, written to churches. And for the most part are very uplifting. The letters to the Galatians and the Corinthians address some very serious errors occuring within those local congregations, however. And the letters to the churches in the Book of the Revelation of Jesus Christ were likewise encouraging, admonishing, and with some rather stern warnings. There will always be the necessity of such communications from God's men.
The content of our NT epistles remind us that pastors, deacons, elders, prophets, teachers, evangelists, mature men and women of the faith, and so forth, are charged with correcting errors that often creep into the church. In Paul's day heresey sometimes came into the church through the Judaizers who followed him around spouting their damnable doctrines. In our day it is more than likely coming to our people through their televisons. The God-called servants within each local congregation are charged with the oversight of their flock in order to prevent or cast out those damnable heresies and their sowers (I Pet. 5:1-4; I Cor. 5:13b; Gal. 1:8-9).
In the early days of my faith, I would become angry over the likes of The PTL Club and Oral Roberts and the Hagins and the Copelands, and some of my friends would wonder why I got so upset over these "men of God." Later, my wife would wonder the same. And one day I read "For I am jealous for you with godly jealousy" (II Cor. 11:2) and realized that this was my heart, this was why I became so angry when witnessing the church being poisoned with the heresies of the "health and wealth" false teachers.
But the godly jealousy that Paul wrote of and that experienced by our brethren throughout the world is also stirred into action by the liberals of our day who deny the resurrection, the virgin birth, justification by grace alone through faith alone through the gospel alone, and the absolute veracity of the written Word of God. And we see before our very eyes the need for our proclaiming the gospel to our own people, sitting in our pews in their unbelief...and totally convinced otherwise.
So are we to preach John 3:16 every week? Of course, not. But, everything we preach and teach is to be Christ-centered and faith building. Our aim each week is to be faith.
How can we have godly families and marriages? Through practicing the principles laid out in the Word of God that are possible only through the finished work of Christ. How can I be more successful at work? By practicing doing everything as unto Him. How can I have assurance that when I die I will be with the Father eternally? What am I to do when I have sinned big time? How is it possible for God to continually forgive me? Why should I expect God to bless me at work or in my marriage or with my kids? It is all through the gospel that we are to answer these questions. It is through the uncompromising preaching of the Word of God that the unregenerate among us will hear the truth and, if God so wills, be granted repentance and life.
Brothers, don't imitate Joel Osteen and begin with a joke and end with an invitation to "accept Jesus into your heart" when you haven't even mentioned Him or the gospel in your sermon. Preach the Word! And watch the Holy Spirit do His work in your church.
Remember, His work will stir up the good, the bad, and the ugly. All signs of an open door of ministry.