Sex
“Marriage is to be honored by all, and the marriage bed kept undefiled, because God will judge the sexually immoral and adulterers.”
Definition
Sex is the physical union God designed for the “lifelong marriage covenant of one man and one woman,” created good and given for “physical union, fruitful labor, procreation, and fellowship.”1 Genesis grounds this design in creation itself: God made humanity “male and female” (Gen. 1:27), declared it “not good” for the man to be alone (Gen. 2:18), and united them as “one flesh” (Gen. 2:24). Because sex belongs to marriage by God’s own design, Scripture commands that it be kept “exclusive and celebrated in marriage alone.”1
Biblical Basis
Genesis 2 traces the creation of the woman and the union that follows. God, having made the man, declares “it is not good that the man should be alone; I will make him a helper fit for him” (Gen. 2:18). When the woman is made, the man greets her as his own: “this at last is bone of my bones and flesh of my flesh” (Gen. 2:23), and the narrator draws out the pattern this establishes for every marriage after: “a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh” (Gen. 2:24). Magnuson reads these two chapters together as the foundation of the whole Bible’s sexual ethic: “Genesis presents this union as the lifelong marriage covenant of one man and one woman designed for the purposes of physical union, fruitful labor, procreation, and fellowship.”1
Later Scripture states the same design as command. Paul tells the Corinthians that sexual sin is unlike other sin in how directly it implicates the body itself: “the sexually immoral person sins against his own body. Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God?… So glorify God in your body” (1 Cor. 6:18-20). He tells the Thessalonians plainly that “this is the will of God, your sanctification: that you abstain from sexual immorality; that each one of you know how to control his own body in holiness and honor, not in the passion of lust like the Gentiles who do not know God” (1 Thess. 4:3-5). Hebrews states the positive counterpart to both warnings: “marriage is to be honored by all, and the marriage bed kept undefiled, because God will judge the sexually immoral and adulterers” (Heb. 13:4).
Doctrinal Significance
Magnuson traces sex through the same pattern Scripture traces everything else through: creation, fall, and redemption. What creation ordered toward a lifelong, one-flesh, procreative marriage covenant, sin disorders at every point once its “objective design and purpose” is rejected: marriage’s status as an exclusive, permanent covenant, its ordering toward children rather than only adult pleasure, and the given complementarity of male and female are each denied in turn once the first rejection is made.1 None of this leaves sex, for those in Christ, beyond repair. Paul names sexual sin plainly among what excludes a person from God’s kingdom, then immediately adds that this described some of the Corinthians themselves, past tense: “such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God” (1 Cor. 6:9-11).1