Secular Americans often see Christians as anti-sex. Pastors preach about the evils of premarital sex, warn against pornography and masturbation, and insist on marital fidelity. But the Bible actually suggests that abstaining from sex can, in very limited and specific circumstances, be a sin.

“In the spirit of 1 Corinthians 7, married couples must make sure you’re coming together to keep Satan at bay,” Vancouver pastor Mark Clark, author of the book The Problem of God: Answering a Skeptic’s Challenges to Christianity, told PJ Media in an interview on Tuesday.

Clark suggested that it certainly can be a sin for married couples to abstain from sex with one another. Nevertheless, he immediately insisted, “I say that with 40 different footnotes.” He listed important reasons why couples might have to avoid sex — health concerns, past psychological trauma, emotional disconnect, and others.

The author cited 1 Corinthians 7, however, a passage where St. Paul urges wives and husbands to have sex frequently, to stave off “the temptation to sexual immorality.”

Paul wrote, “The husband should give to his wife her conjugal rights, and likewise the wife to her husband. For the wife does not have authority over her own body, but the husband does. Likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another, except perhaps by agreement for a limited time, that you may devote yourselves to prayer; but then come together again, so that Satan may not tempt you because of your lack of self-control” (1 Corinthians 7:3-5).

While Paul expressed his personal desire for all Christians to remain single, he stressed that if Christians are tempted to sexual immorality, they should marry so that they can have sex in its proper context.

In his book, Clark wrote that Paul’s word to couples “is a positive challenge to the sad state of sex in many marriages today. … What I have said to couples in counseling over the years is that given a generally healthy marriage, if you are going weeks, or months without having sex with your spouse, you are not fulfilling your conjugal duties (and delights!).”

Many Christians emphasize the temptations to go too far with sex (adultery, premarital sex, pornography, etc.), but usually neglect the temptation to not go far enough. “In reality, not going far enough is just as unbiblical,” the pastor wrote.

Clark cited a group of Puritans who excommunicated a man from the church and put him under church discipline for not going far enough. What was his crime? “He refused to have sex with his wife for two years.”

“Sin would be a strong word, but I do think there are times when it could become that,” Clark told PJ Media. “Not sleeping with a spouse for two years, for example.”

The pastor insisted that sex “was obviously part of the biblical design with regard to pleasure, and to deny one another would be like not talking to a spouse for two years. We would all say you can’t do that.”

Sex is an important part of a healthy marriage, but the Bible presents no clear benchmark as to how often a married couple should exercise each other’s “conjugal rights.” Clark pointed to Martin Luther on this. “Twice a week seems to be enough to stave off the Tempter,” Luther wrote.

“I do hold twice a week up as the goal, for a couple with a normal relationship,” Clark told PJ Media. Especially in the modern world, with pornography only a click away on the Internet, the author insisted that frequent sex in marriage is a powerful tool to stave off temptation — by enjoying the great good of sex in the way God designed it.

Even so, he insisted that every couple is different and that there are many reasons to avoid sex, including health concerns, previous emotional abuse, and (of course) if the couple wants to abstain for a time in order to worship God.

Christianity teaches that each human being will live forever, but marriage is an institution only for the Earth. In heaven, there will be no marriage. So it makes perfect sense to abstain from sex — by mutual agreement and for a limited time — in order to worship God.

Finally, Clark was not giving carte blanche to husbands who might want to have sex more frequently than their wives are comfortable with (or vice versa). Rather, this should be a call for either spouse who might be withholding sex for one reason or another to examine whether or not that is a biblical position.

Jesus described marriage as a “one flesh” union between husband and wife, and sex is one key component of that. The entire union is also emotional, spiritual, practical, and economic — a binding of love in which Christians are called to emulate the sacrificial love of Jesus Christ.

If either spouse is uninterested in sex for whatever reason (besides a devotion to God or concerns about physical or emotional health), God may be calling that person to show sacrificial love by having sex anyway. This does not mean the other person should just demand it — both spouses need to love selflessly.

Christian marriage is about much more than just sex, but it is also about sex. It is possible to sin by not having sex enough, especially if a spouse is withholding sex out of pride, malice, or resentment. But it is also a sin to force your spouse to have sex.

Neither St. Paul nor Mark Clark suggested that married Christians have to have sex a certain number of times per week, but they did encourage spouses to love one another physically, emotionally, and spiritually — and a key part of that happens between the sheets.