The recent charge filed against Dr Scott Oliphint re his teaching about divine immutability in the OPC has raised for me the important question, “What is heresy?” Dr Oliphint has not been accused of teaching heresy but the charges do specify that he is teaching contrary to the Scriptures and the Westminster Standards.
There are two equally problematic errors to avoid in situations like this: the refusal to name “heresy” out of a desire not to be divisive or mean-spirited and the use of the term to cover matters clearly not delineated in Scripture as primary issues that will issue in the loss of salvation. Historically, the church hammered out the meaning of the terms hairesis and heterodoxia in the first five centuries to entail the conscious and willing embrace of teaching that undermines the gospel, preventing both the teacher of it and those who embrace his/her teaching of being saved.
This is vital to note: a person who embraces heresy is not a Christian according to Christian tradition. Thus, when an author very critical of an historical Baptist figure described his teaching as being the “mother of all heresies,” and I responded to him that this meant that this historical individual was not a saved person, and the author replied to me that this was not the case at all: of course, he was saved, he said—then I had to admit to him that this did not make any sense to me. If a person knowingly teaches heresy and as such is a heretic, then, by the way Christianity has defined “heresy,” this person cannot be a Christian.
Now, a casual perusal of the Web will reveal both errors on display, a matter for deep concern. Not all who say “Lord, Lord,” shall inherit the kingdom: there are theological errors that are so profound that they undermine the basics of Christian doctrine—doctrines such as justification (see Galatians 1–2), the resurrection of the body (see 1 Cor 15; 2 Tim 2), the Incarnation (see 1 John 4; 2 John), the goodness of the material creation and perverse views of marriage (see 1 Tim 4), the deity of the Lord Jesus (John 8:24, where it is vital to note that the Greek simply has ego eimi—a reference to Exodus 3:14), and the Trinity (Matthew 28 and throughout the New Testament)—and those who teach them must be identified as wolves in sheep's clothing.
But, on the other hand, and social media has provided a massive platform for those so inclined towards the second error, the term “heresy” has been so bandied about that it is in danger of losing its significance. So, for example, we find political positions not to one's liking branded as heresy (even though the New Testament does not specify details here), or eschatological stances at odds with one's own described as heretical (despite the fact that solid Bible-loving Christians have disagreed over details of the end times), or perspectives regarding societal issues labeled heterodox (again, an arena where we must agree to disagree—Romans 14 is so helpful here).
Scripture, we must ever affirm, is “profitable for doctrine, for reproof, for correction” that the Church might be “perfect, thoroughly furnished unto all good works' (2 Timothy 3). Scripture alone can determine what is heretical.