I would suggest, however, that debate is both Biblical and essential to a healthy church. It is through challenge and debate that heresies are exposed. Just as Paul withstood Peter when Peter was in error (Galatians 2), men of God throughout the ages have battled error with voice and pen. What false doctrines would have prevailed if these men had just "agreed to disagree"?
A Denial of Jesus' Humanity
Gnosticism was one of the earliest heresies to plague the church. The Gnostics believed that the material world was evil, having been created not by God, but by a fallen angel. They taught that the souls of men were trapped in their human bodies awaiting a messenger with divine knowledge to release them. For Christian Gnostics, that divine messenger was Jesus Christ. Since the body is evil, reasoned the Gnostics, Jesus could not have possessed a real human body. He only appeared to have a human form. Thus Gnosticism denied the humanity of Jesus Christ. The great apologists of the early church - Irenaeus, Clement of Alexandria, Tertullian, Origen - defended the orthodox faith against the Gnostics.
A Denial of Jesus' Divinity
Early in the fourth century, Arius argued that Jesus was not co-eternal with God the Father. His position, known as Arianism, taught that Jesus was created by God prior to God's creating the world. Thus Arianism denied the divinity of Jesus Christ. The question of Jesus' divinity was debated at the Council of Nicea in 325 AD. Eusebius of Nicomedia represented the Arian position, and Alexander of Alexandria opposed him. Initially, the majority of the bishops at the council had little interest in the issue beyond a concern that it would divide the church. But after listening to Eusebius's apology for Arianism, they declared it a heresy. The Nicene Creed was written specifically to address the divinity of Christ. Arianism lingered in the church long after the Nicene Council, however, and Alexander's successor, Athanasius, continued to speak and write against it.
A Denial of Original Sin
Almost 100 years later, the Council of Carthage denounced the teachings of Pelagius as heresy. Pelagius denied original sin. He taught that man is born good and chooses to sin. Therefore, man can again choose to obey the Law without divine aid. Augustine of Hippo strenuously opposed the teachings of Pelagius.
A Denial of the Finished Work of Christ and the Humanity of Christ
Transubstantiation, the Roman Catholic teaching that the real presence of Christ is in the bread and the wine, "strikes at the very heart of the Gospel" (J.C. Ryle, Five English Reformers). Jesus cried, "It is finished" on the cross. But if Christ is crucified again and again each time Mass is performed and the sacraments administered, then His work was not finished at the cross. Furthermore, if Jesus' body is truly present in the bread and the wine, then his body was not fully human. The Reformers preached against and wrote against the doctrine of transubstantiation, and for their refusal to affirm this false doctrine, many of them were burned. John Hooper, Rowland Taylor, Hugh Latimer, John Bradford, and Nicholas Ridley went to the stake for refuting transubstantiation.
A Denial of the Inerrancy and Plenary Inspiration of the Scriptures
"Shall the Fundamentalists win?" asked Harry Emerson Fosdick in 1922.
"They insist that we must all believe in the historicity of certain special miracles, preeminently the virgin birth of our Lord; that we must believe in a special theory of inspiration—that the original documents of the Scripture, which of course we no longer possess, were inerrantly dictated to men a good deal as a man might dictate to a stenographer; that we must believe in a special theory of the Atonement—that the blood of our Lord, shed in a substitutionary death, placates an alienated Deity and makes possible welcome for the returning sinner; and that we must believe in the second coming of our Lord upon the clouds of heaven to set up a millennium here, as the only way in which God can bring history to a worthy denouement."
Fosdick represented the liberal theology that had permeated the mainline denominations and their seminaries in the early 1900's. Of the men who opposed liberalism, perhaps none was so dedicated as J. Gresham Machen, who devoted his life to teaching and defending the Scriptures and to opposing liberal theology. Machen's life was marked by controversies - controversies with high-profile professors and pastors, controversies in the seminary, and controversies in the church.
There's no shortage of controversy in Christianity today, and much of it is debated online where high profile pastor/teacher/authors are critiqued and challenged by bloggers. Is this healthy for the church, or is it mean-spirited and divisive? Are the bloggers merely debating how many angels can dance on the head of a pin? I think not.
Shortly before he was burned at Gloucester, Bishop Hooper wrote:
But now is the time of trial, to see whether we fear more God or man. It was an easy thing to hold with Christ while the Prince and the world held with Him; but now the world hateth Him, is the true trial who be His. Wherefore, in the name and in the virtue, strength, and power of His Holy Spirit, prepare yourselves in any case to adversity and constancy. Let us not run away when it is most time to fight. Remember, none shall be crowned but such as fight manfully. . . .
In an era where ancient heresies are rapidly re-emerging in postmodern garb, there is more than ever a need to earnestly contend for the faith. We have a responsibility to future generations, yet the feminized Church is bereft of warriors. Where are the modern-day Augustines and Hoopers and Machens? Their voices are lost at sea, drowned in an ocean of platitudes: "Let's agree to disagree." "Let's be charitable." "Let's not split hairs over doctrine." But now is the time of trial . . . let us not run away when it is most time to fight.