Sex is not only a short word but one with a tiny presence in many mainline churches. At least, sex is one of those topics “good” pastors stay away from because sex is a private matter. I agree, it is one of the most intimate of privacies, but I might not be a “good” pastor. The church needs to talk about sex—or more formally, sexual ethics—because the world is talking about it. Your children and grandchildren are talking about. Your coworkers, siblings, and neighbors are talking about. If they or you aren’t talking explicitly about sex, it surrounds you in books, social media, TV commercials, and nearly every corner of the world wide web. This is why having a biblical worldview on sex is so important.
If you do hold to the Christian sexual ethic, you have likely discovered that much of Western society criticizes it as something antiquarian at best and at worst repressive and hateful. This is why knowing the biblical context is so helpful. Those critiques of biblical sexuality betray they are ignorant of the world of the Bible. In the First Century Roman Empire, when the New Testament was being written, it wouldn’t be unethical for men to do whatever they wanted to women. Concubines, prostitution, homosexuality, pornography, rape, and pedophilia were at best ignored and at worst commended. In this world of sexual license, Christianity actually provided both protections and liberation for women to no longer be mere objects of sexual desire but a valued and necessary half of a monogamous marriage.
It is to that end the New Testament forbids “sexual immorality.” The Greek word often translated this way is porneia, which simply refers to sexual activity, but when viewed through the biblical lens is all sexual activity outside of a monogamous, heterosexual marriage covenant. Since porneia has such a wide range of meaning, the list of sexual immorality anathema to Christians can be and is quite long. From Scripture, it at least includes fornication, bestiality, adultery, homosexuality, rape, pornography, incest, pedophilia, cohabitation, transgenderism, polygamy, sodomy, and perhaps more (Lev., 1 Cor., & 1 Thess.)
It is important to note that just because a Christian holds to the biblical sexual ethic does not mean he or she is incapable of committing sexual sin. In fact, we know many faithful believers who have fallen into this snare—from ancients like King David to contemporaries like Ravi Zacharias. Thankfully, God is quick to forgive when we are quick to repent, turning from sin and trusting in Christ. Nevertheless, if we are truly redeemed and regenerated, then we cannot approve of sexual sin. Moreover, and this I see growing too much and too quickly, we cannot seek to change the biblical sexual ethic. God has spoken on what is pleasing in His sight. What pleases God is a one-man/one-woman marriage covenant where husband and wife enjoy the divinely appointed place of sex.