Carl Trueman wrote this in March 2010 after the Tiger Woods saga:

Some years ago I found the argument of John Armstrong’s excellent book The Stain That Stays utterly convincing: post-conversion adultery, unlike other sins, is the one which permanently excludes one from leadership or office-bearing in the church; of course, there is forgiveness and restoration to fellowship for those who repent and ask for such; but as far as leadership goes, it’s over. I still point to that book, especially the superb last chapter on avoiding sexual sin, as required reading for men going in for ministry.

I promptly added that book to my reading list, and I finally read it this week.

John H. Armstrong. The Stain That Stays: The Church’s Response to the Sexual Misconduct of Its Leaders. Fearn, Scotland: Christian Focus Publications; Reformation and Revival Ministries, 2000.

Since writing this book, John Armstrong has shifted towards a big-tent evangelicalism and away from the conservative evangelical circles he used to be a part of (hence the foreword by Kent Hughes and endorsements by Al Mohler, John MacArthur, and Tom Nettles).

The book’s style is a bit cumbersome, but it’s an edifying read about a deadly serious issue. Here are Armstrong’s eight suggested ways that pastors should plan to prevent sexual sin (pp. 174–81):

1. “Understand the nature of sexual temptation.” “In two areas, traveling and counseling, a pastor must take precautions.”
2. “Understand the power of the seductive woman.” “The pastor must be especially careful to guard himself when he detects the first mannerisms that indicate a woman may have feelings that are beyond those of a healthy and pure relationship.”
3. “Guard your mind.” “The pastor must guard his mind by staying away from explicitly erotic material, as well as television programs and images that fuel the fires of lust. . . . Pornography surrounds us, acting as a poison that corrupts healthy sexuality.” [Cf. Joe Tyrpak, “Help for Fighting Lust: A Meditation Plan“; Mike Salvati, “The God of Truth and the Lies of Porn.”]
4. “Cultivate and protect your own marriage.” “This seems to be the plainest meaning of the wisdom given in Proverbs 5:15–23: You must enjoy your wife physically and her alone.”
5. “Take precautions as you minister.” “The wise pastor cannot be overly careful.” [Cf. Mark Minnick, “Maintaining Moral Purity in the Ministry.”]
6. “Maintain relationships where accountability is real.” “Every pastor needs several relationships where he is mutually accountable for his actions and relationships with others.” [Cf. Phil Gons, Matthew Hoskinson, and Andy Naselli, “Accountability.”]
7. “Cultivate your spiritual, emotional, and physical well-being.” “You must know yourself and take care of your body and soul to remain strong.”
8. “Consider regularly the consequences of sexual sin.” “What will this sin mean to your wife? Your children? Your congregation? Your closest friends? Your future ministry? We need to do this because the outcome of this particular sin is so deceiving.” [Cf. Randy Alcorn’s “purity principle“: purity is always smart; impurity is always stupid.]

I don’t agree with Armstrong’s thesis, but his book rightly treats sexual sin soberly. I find D. A. Carson’s argument more compelling: “Do You Think That a Fallen Christian Leader Can Ever Be Restored? If Not, Why Not? But If So, under What Conditions?” The Southern Baptist Journal of Theology 4.4 (2000): 87–89.

Update: Cf. Andrew David Naselli, “Is Every Sin Outside the Body except Immoral Sex? Weighing Whether 1 Corinthians 6:18b Is Paul’s Statement or a Corinthian Slogan,” JBL 136 (2017): 969–87. In 1 Cor 6:18b–c, Paul writes, “Every sin, whatever a person commits, is outside the body, but the sexually immoral person sins against his own body.” My essay weighs whether 1 Cor 6:18b is Paul’s statement or whether Paul is quoting a Corinthian slogan, and it concludes that the second view is more plausible (contrary to how John Armstrong argues in the above book).