The Henrician Canons of 1535 referred to heresy as "fireballs by which the Church is inflamed and continues to burn miserably". These 16th-century reformers said the devil "daily piles up even more firewood in the shape of false opinions". These would be thrown by Satan into the Church, to cause as much trouble as possible and lead people astray.

Jesus himself was a controversialist and refuted false teaching. He had public debates with contemporary leaders about doctrine. In Christ the Controversialist, John Stott says: "They did not agree with Him, and He did not agree with them...He was not 'broad-minded' in the popular sense that he was prepared to countenance any views on any subject." Stott concluded: "As a result of His loyalty to the truth, He was not afraid to dissent publicly from official doctrines (if He knew them to be wrong), to expose error, and to warn His disciples of false teachers. He was also extremely outspoken in His language, calling them 'blind guides', 'wolves in sheep's clothing', 'whitewashed tombs' and even a 'brood of vipers'...we seem in our generation to have moved a long way from this vehement zeal for the truth which Christ and His apostles displayed."

The apostles continued to fight against heresy after Jesus ascended into heaven. The whole of 1 Corinthians deals with issues of heresy, apostasy and schism in the Church. 1 and 2 Timothy and Titus address pastors working in contexts where there is much false teaching. Acts and the epistles are full of advice on how to deal with heretics.

Definitions of heresy include the idea that a person should only be classed as a heretic (and therefore avoided) if they persist in their false teaching. First, as Paul says in 2 Timothy, they should: "be gently instructed, in the hope that God will grant them repentance leading them to a knowledge of the truth, and that they will come to their senses and escape from the trap of the devil, who has taken them captive to do his will." (2:25-26)

WATCH AND WELCOME

In 2 John, the Church is told to "watch out" for false teachers. "If anyone comes to you and does not bring [true] teaching, do not receive him into your house or give him any greeting, for whoever greets him takes part in his wicked works" (v8-11, ESV).

When John says we should not give false teachers "any greeting", he isn't forbidding us from saying hello in a literal sense, but offering Christian hospitality to those who travel around speaking about Jesus. That kind of hospitality is to be denied to those who aim to deceive, so that no help is given to their doctrine. As David Jackman says in his commentary on 1 John: "We must not do anything which 'takes part in the wicked works' of those who promote soul-destroying heresy. Love demands that we deny them platforms and the ability to continue propagating their deception, as far as we are able. We must not be complicit in the spreading of deceptive lies."

PAUL'S WORDS HAVE PROVED PROPHETIC IN EVERY GENERATION: "AFTER MY DEPARTURE FIERCE WOLVES WILL COME IN AMONG YOU."

This is strong medicine. Is heresy really so bad? Yes. Some have even spoken of "the cruelty of heresy". As C FitzSimons Allison put it in his book of the same name: "We are susceptible to heretical teachings because, in one form or another, they nurture and reflect the way we would have it be rather than the way God has provided, which is infinitely better for us...heresies pander to the most unworthy tendencies of the human heart. It is astonishing how little attention has been given to these two aspects of heresy: its cruelty and its pandering to sin."

This is a topical observation. Revelation 2 shows us that heresy and immorality go together, and penetrate into the heart of churches. Yet Jesus will not let this pass unnoticed. He will not only judge those who spread falsehood, but also calls those who tolerate it without action to repent. We are to hold on to the true gospel in the face of such temptations and threats, hating the doctrines and practices that might lead us away from devotion to the Lord.

HERESIES TODAY

Variants of the false teachings tackled by Paul are always popping up. There will always be people who deny that justification is by faith alone, who question the reality of substitutionary atonement or bodily resurrection. Paul said that people who behave in certain ways "will not inherit the kingdom of God" (1 Corinthians 6:9) and yet his ethical teachings, particularly on sex, are often denied today.

The Christian view that sex outside of marriage between one man and one woman is a sin seems to be under attack all over the world. Identity politics has infiltrated the Church and overturned not simply basic doctrines such as creation, the Fall and repentance, but also attacked the fundamental building blocks of human flourishing such as marriage, family and the long-established sexual ethics that gave Western civilisation its stability.

In his commentary on Titus 3, the great medieval theologian Thomas Aquinas warned that "if a person were to maintain that God is not triune and one, or that fornication [sex outside of marriage] is not a sin, he would be a heretic." As it was in the beginning, is now, and ever shall be.

WE HAVE MOVED A LONG WAY FROM THE VEHEMENT ZEAL FOR THE TRUTH WHICH CHRIST AND HIS APOSTLES DISPLAYED

The creation-denying Gnostic heresies that were popular in the second century have also made a comeback. Some think that what we do with our physical bodies does not matter because the 'spirit' is the most important thing, or question the original distinction of humanity into male and female. Accommodation of local social, commercial or religious customs is a perennial and persistent pressure on the Church, which can lead to us denying the truth of God's unerring word.

Heresies about the Trinity, or the person of Christ remain a perpetual source of error in the Church. A 2018 survey of UK evangelicals by Ligonier Ministries found that 35 per cent agreed with the statement "the Holy Spirit is a force but not a personal being". Most people disagreed with the statement "There will be a time when Jesus Christ returns to judge all the people who have lived", despite these words being almost identical to those contained in the Apostles Creed. The survey thus revealed widespread denial of classic Christian teaching among churchgoers in the UK.

The prosperity gospel is a huge problem in many parts of the global Church. Although we take up our cross and follow a crucified Messiah who had "nowhere to lay his head" (Matthew 8:20, ESV), the internet abounds with examples of preachers such as Joel Osteen who promise "your best life now" if we only have enough faith. Health and wealth will follow if we subscribe to what Oral Roberts calls "God's formula for success and prosperity". Unsurprisingly, the formula often involves giving money to their ministries.

IN CHRIST ALONE

The syncretistic mixing of other religious ideologies and practices into Church teaching, and the universalism this often fosters, also remains a perpetual problem. Jesus was clear that: "No one comes to the Father except through me" (John 14:6, ESV). The apostles preached that "Salvation is found in no one else, for there is no other name under heaven given to mankind by which we must be saved" (Acts 4:12). Yet some teach that the world's religions are many paths up one mountain, and can be mixed without any ill-effects. It is not uncommon for some African Christians to combine their faith with practices from African traditional religions, which are at odds with Christian belief. "We will all be saved in the end" is not a Christian teaching, but is a common belief in both pulpits and pews.

The Western idolatries of sex and celebrity have also torn the fabric of the Church almost everywhere. The scandals (often involving sex, power or money) surrounding prominent Christian leaders such as Ravi Zacharias, Jonathan Fletcher, Steve Timmis, John Smyth, Mark Driscoll and others have shown the dangers of equating power and fame with godliness.

The apostle John warned about a leader called Diotrephes, "who loves to be first" (3 John 9-11). In the same way, some people feel entitled to prominence. Jesus contrasted such undeserved arrogance with his own example: "You know that those who are regarded as rulers of the Gentiles lord it over them, and their high officials exercise authority over them. Not so with you. Instead, whoever wants to become great among you must be your servant, and whoever wants to be first must be slave of all. For even the Son of Man did not come to be served, but to serve, and to give his life as a ransom for many" (Mark 10:42-45).

The battle against heresy is ongoing. Paul's words have proved prophetic in every generation: "after my departure fierce wolves will come in among you, not sparing the flock; and from among your own selves will arise men speaking twisted things, to draw away the disciples after them" (Acts 20:29-30, ESV).

A DEEPER TRUTH

But heresy can have a positive side too. Having to combat error forces us to deepen our grasp of God's revealed word in ways we might not otherwise have thought to consider.

As St Augustine said: "while the hot restlessness of heretics stirs questions about many articles of the Catholic [universal] faith, the necessity of defending them forces us both to investigate them more accurately, to understand them more clearly, and to proclaim them more earnestly; and the question mooted by an adversary becomes the occasion of instruction."

According to scripture, heresy is pernicious and poisonous. So why is it so unthinkable that it should be rooted out in the Church today? Why are those to whom we have entrusted this task not keener to safeguard our spiritual health and wellbeing?

There is a danger that if we don't stand firm and oppose heresy, we end up sliding into compromise and heresy ourselves, since we are always inclined to corruption no matter how pure our Church may be on paper. But it is equally dangerous to fight in a way that loses sight of our Lord Jesus.

In the Bible, both Jude and James tell us to contend by having mercy on those who doubt and by saving those who wander (Jude 17-23; James 5:19-20). If we are servants of the Lord, we will not be "quarrelsome" but "kind to everyone, able to teach" (2 Timothy 2:24). Our relationships must remain sufficiently respectful and dignified that we are able to speak in a way that they can hear and learn and, by God's grace, repent.

Dr Lee Gatiss is the director of Church Society and a lecturer in Church history at Union School of Theology. He is the author of the newly revised and expanded book Fight Valiantly!: Contending for the faith against false teaching in the church (Lost Coin Books)