“It may not always be easy to determine whether a disagreement is merely petty or truly weighty, but a careful, thoughtful application of biblical wisdom will usually settle whatever questions we may have about the relative importance of any given truth.  Scripture makes clear, for example, that we must take a zero-tolerance stance toward anyone who would tamper with or alter the gospel message (Galatians 1:8-9).  And anyone who denies the deity of Christ or substantially departs from His teaching is not to be welcomed into our fellowship or given any kind of blessing (2 John 7-11).

The principle is clear: the closer any given doctrine is to the heart of the gospel, the core of sound Christology, or the fundamental teachings of Christ, the more diligently we ought to be on guard against perversions of the truth – and the more aggressively we need to right the error and defend sound doctrine.

Differentiating between truly essential and merely peripheral spiritual truths does require great care and discernment.  The distinction is not always immediately obvious.  But it is not nearly as difficult to draw that line as some people today pretend it is.  Even if the line does seem a little fuzzy here and there, that’s no reason to eliminate the distinction altogether, as some postevangelicals seem determined to do.

Many today are advocating an ultraminimalist approach, paring back the list of essential doctrines to what’s covered by the Apostles’ Creed (or in some cases, an even shorter list of very broad generalities).  That doesn’t really promote harmony; it merely muddies all doctrine.  After all, many rank heretics, ranging from Unitarians to Socinians to Jehovah’s Witnesses, will formally affirm the Apostles’ Creed.  The problem is that they don’t agree on what the creed means.  Even the largest branches of Christian belief – Catholics, Eastern Orthodox, and Protestants – don’t agree among themselves on the meaning of crucial expression in the creed.  It is useless as a standard by which to measure which truths are primary and which ones are secondary.

But Scripture suggests that the gospel, not a third-century creed, is the best gauge for determining the true essentials of Christianity.  If you genuinely understand and affirm the gospel, you will automatically have sound views on justification by faith, substitutionary atonement, the deity of Christ, the historicity of the resurrection, the truthfulness and authority of Scripture, and every other doctrine that is “of first importance” (1 Corinthians 15:3).  Conversely, if you go astray – even subtly – on any vital principle of gospel truth, your whole worldview will be adversely affected.  Misconstrue the gospel or adapt it to suit a particular subculture’s preferences and the inevitable result will be a religion of works and a system that breeds self-righteousness.

That is exactly what Jesus’ conflict with the Pharisees was all about.  They represented a style of religion and a system of belief that was in direct conflict with the very heart of the gospel He proclaimed.  He offered forgiveness and instant justification to believing sinners.  Israel’s religious leaders manufactured massive systems of works and ceremonies that in effect made justification itself a human work.  In the words of the apostle Paul, “they were ignorant of God’s righteousness, and seeking to establish their own righteousness” (Romans 10:3).

There was simply no way for Christ to avoid conflict with them.  So instead, He made the most of it.  He used their false religion as a foil for the truth He taught.  He let their hypocrisy serve as a backdrop against which the jewel of His holiness shone more brightly.  And He set His grace in opposition to their self-righteousness in a way that made the distinction between justification by faith and works-religion impossible to miss.”

Copied from the prologue of John MacArthur’s book, “The Jesus You Can’t Ignore: What You Must Learn From the Bold Confrontations of Christ.”