If you would like to read the full version then you will need to buy the book, but here are some extracts to whet your appetite:
[Martin Downes] When engaged in polemics it does not take too long before strong words can be spoken against your character. The great New Testament scholar Gresham Machen was often vilified and subject to personal attacks. Why does this happen and how should you handle it?
[Ligon Duncan] Expect it. Those who teach aberrant doctrine successfully are always, always possessed of two qualities – pride and intelligence. Both of these will often feature in their defense against critiques of their work.
Be determined to know their view (and to be able to articulate it) better than they know it themselves. If you cannot to state the position of your opponent, in your own words, in a way in which they can recognize themselves, then you do not yet understand your opponent’s position and you are not yet ready to enter into polemics with it. Following this counsel would, by the way, cut out 99% of theological discussion on the internet!
Refuse to take the insults thrown back at you personally. You are a servant of the word. And if a servant, you must be prepared to be treated like a servant. The only thing that matters is the glory of God, the vindication of the word, the upholding of the truth, the faithful proclamation of the Gospel and the good of souls. Let them cast what aspersions they may. You only crave the affirmation of One.
[Downes] Heresy is rarely presented in its true colours. Advocates always stress that their view is both biblical and pastorally beneficial. What principles should we follow to avoid being taken in by these schemes?
[Duncan] Ask yourself questions about their view of Scripture. Whether they claim to have a high view of Scripture or not, do their views tend to undermine the final authority of the Bible.
Ask yourself questions about their doctrine of God. Do their views tend to undermine some aspect of his sovereignty or trinity?
Ask yourself questions about their doctrine of Christ. Do their views tend to undermine his claims of full humanity and full deity, or compromise the sole sufficiency and absolute necessity of his saving work?
Ask yourself questions about their doctrine of sin. Do their views deny original sin, or tend to undermine or scale down the sinfulness of humanity?
Ask yourself questions about their view of the Gospel. Do they teach or imply a universalism? Do they compromise the sovereign initiative of God’s grace in salvation? Do they find ways to incorporate man’s deeds in his acceptance with God?
Ask yourself questions about their view of the church. Do they view the church as over the Bible or equal to the Bible, or do they realize that God’s word brought the church into being and thus rules over the church? Do they view the sacraments as justifying or sanctifying? Do they acknowledge that the church has both visible and invisible aspects (that is, that there is an external and internal aspect to the church, and that the church is both local and extended in space and time)?
Ask yourself questions about their view of the end? Do their views promote escapism and retreat, or triumphalism and worldliness? Do they believe in literal return of Christ? Do they believe in heaven/the age to come? Do they believe in the bodily resurrection and final judgment?
Ask yourself questions about their life. Do they show signs of humility or of spiritual pride? Do they bear the marks of the fruit of the spirit? Has their teaching made them more humble, Christ-exalting, Scripture-obeying, world-denying, Gospel-loving, people-serving, truth-treasuring and evidently submissive to proper spiritual authority.
Finally, (1) know your Bible; (2) know your church’s confession or statement of faith; (3) know about the heresies of the past (because Satan is unoriginal).
Roger Nicole and John Frame both offer good advice on how to engage in polemics.
[Downes] If the doctrine of justification by faith alone is still the doctrine by which the church stands or falls what are your hopes and fears for evangelicalism and for confessionally Reformed churches on this very point?
[Duncan] I do not fear and I am deeply concerned.
I do not fear. The Lord will build his church, and even the very gates of hell will not be able to resist the onslaught of the kingdom.
That being said, I am deeply concerned. The spirit of the age is compromise and defection. What is required of ministers in times of spiritual unfaithfulness and doctrinal downgrade and defection is steadfast, unyielding devotion to the truth. We must stand fast. And we must out-live, out-rejoice, out-love, out-preach, out-serve and out-die the false teachers and errorists.
And I am cautiously optimistic. Even in the short run. The so-called “young, restless and Reformed” crowd shows many evidences of resisting the “justification downgrade.” Hang in there, brothers!