Here is John Newton’s response to a minister who was preparing to write an article criticizing another minister for his lack of orthodoxy. (original source here)
As you are likely to be engaged in controversy, and your love of truth is joined with a natural warmth of temper, my friendship makes me solicitous on your behalf. You are of the strongest side; for truth is great, and must prevail; so that a person of abilities inferior to yours might take the field with a confidence of victory. I am not therefore anxious for the event of the battle; but I would have you more than a conqueror, and to triumph, not only over your adversary, but over yourself. If you cannot be vanquished, you may be wounded. To preserve you from such wounds as might give you cause of weeping over your conquests, I would present you with some considerations, which, if duly attended to, will do you the service of a great coat of mail; such armor, that you need not complain, as David did of Saul’s, that it will be more cumbersome than useful; for you will easily perceive it is taken from that great magazine provided for the Christian soldier, the Word of God. I take it for granted that you will not expect any apology for my freedom, and therefore I shall not offer one. For method’s sake, I may reduce my advice to three heads, respecting your opponent, the public, and yourself.
Consider Your Opponent
As to your opponent, I wish that before you set pen to paper against him, and during the whole time you are preparing your answer, you may commend him by earnest prayer to the Lord’s teaching and blessing. This practice will have a direct tendency to conciliate your heart to love and pity him; and such a disposition will have a good influence upon every page you write.
If you account him a believer, though greatly mistaken in the subject of debate between you, the words of David to Joab concerning Absalom, are very applicable: “Deal gently with him for my sake.” The Lord loves him and bears with him; therefore you must not despise him, or treat him harshly. The Lord bears with you likewise, and expects that you should show tenderness to others, from a sense of the much forgiveness you need yourself. In a little while you will meet in heaven; he will then be dearer to you than the nearest friend you have upon earth is to you now. Anticipate that period in your thoughts; and though you may find it necessary to oppose his errors, view him personally as a kindred soul, with whom you are to be happy in Christ forever. Continue reading