You shall not commit adultery (Exodus 20:14).
Adultery is a gospel matter. How so? Because God made man in His image—male and female (Gen 1:26). Because the union of a husband and a wife is a picture of Christ and the Church (Song of Songs; Eph 5:32-33). Because this is so, our sexual lives bear witness, either truthfully or falsely, about the character of God and His relationship to His Church. Faithful marriage says one thing. Adultery says another.
Although rarely admitted openly, legal abortion exists to support sexual license. Yet, surprisingly, the U.S. Supreme Court freely admitted this in a comment on Roe v Wade, the 1973 case that made abortion legal in the United States:
The Roe rule’s limitation on state power could not be repudiated without serious inequity to people who, for two decades of economic and social developments, have organized intimate relationships and made choices that define their views of themselves and their places in society, in reliance on the availability of abortion in the event that contraception should fail. The ability of women to participate equally in the economic and social life of the Nation has been facilitated by their ability to control their reproductive lives. The Constitution serves human values, and while the effect of reliance on Roe cannot be exactly measured, neither can the certain costs of overruling Roe for people who have ordered their thinking and living around that case be dismissed.6
In simpler language, the Court argued that sexual license depends upon the availability of abortion. To say it differently, if abortion were illegal, sexual license would need to be forsaken. And that, apparently, is too high a price to pay. The implication is plain—if sexual license must come at the expense of young lives, so be it. The Supreme Court, by its own admission, has ruled to protect sexual immorality by force of law.
The evil of abortion is therefore not limited to the slaying of unborn children. Legal abortion encourages sexual immorality which, even when it does not lead to pregnancy, always brings heartache and destruction. We don’t need the Bible to tell us of the destructiveness of extramarital sex—an honest sociologist knows that premarital or extramarital sex has destructive consequences, particularly within a marriage. In other words, sexual immorality doesn’t work. And therefore God, in His love for mankind, draws a bright line of sexual exclusivity around marriage, so that man and woman can live in faithful and joyful union, to the end they would be blessed and fruitful in marriage, and that the world would thereby behold something of the nature of Christ’s love for the Church.
“Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh.” This mystery is profound, and I am saying that it refers to Christ and the church (Eph 5:31-32).
6 Planned Parenthood v Casey (1992).