In God's program of using men to be witnesses for Him of His provision of salvation through His Son, He first chose a small group of men who were intimately associated with the words and works of Jesus Christ. Most of them were companions of the Lord during the years of His ministry, and it was a requirement that they all be eyewitnesses of the resurrected Lord. The Bible word for these men is Apostles.
It was these men who first carried the good news of salvation from sin to the needy world. The Bible makes it clear that the true church is built upon the foundation they laid. The Apostle Paul said, "According to the grace of God which is given unto me, as a wise masterbuilder, I have laid the foundation, and another buildeth thereon. But let every man take heed how he buildeth thereupon" (I Corinthians 3:10).
They not only did the first work of preaching the Gospel of Jesus Christ and gathering disciples into local churches, but they also left for us a written record of God's blueprint for His church. God never intended that His work be like the "Free Expression" department of the local art show, but that it would follow the patterns He revealed to His chosen witnesses, the Apostles.
There are ramifications to these truths. The Apostles were unique and there are none today. Today, in 2011, we are past the foundation stage of the church and the eyewitnesses of Christ's resurrection are no longer with us. Secondly, the teachings of the, preserved in the Holy Scriptures, continue to be God's authoritative message of real Christianity. Every worldview, religion, or ism in the world rests upon certain precepts accepted by faith. Even atheism has its dogma and its prophets who must be accepted on the basis of some kind of authority claimed.
Those who are Bible-believing Christians need not be bashful about living by the well-authenticated, body of truth of Christianity, the testimony of God's Apostles preserved for us in the Holy Bible.