It is stark in its bold simplicity. It gives no room for special circumstances or exceptions. It doesn’t explain why, but then it doesn’t really need to. The seventh commandment, “You shall not commit adultery” (Exodus 20:14), is self-explanatory. Or so it would seem. Though such disloyalty to one’s partner in marriage would seem to be held in contempt by any society, the fact that God included it in the list indicates that it is a problem of large proportion for the human race. And it indicates that God sees it as a behavior that brings great destruction to any individual and society. If our understanding of Malachi 2:10-16 is right, violation of one’s marriage covenant leads to failure to raise children in the right way.
Our culture is looking for ways to represent adultery as an acceptable alternative to a dead-end marriage or even a healthy thing for a so-so marriage. But God, in his wisdom and concern for the welfare of his children, has clearly spelled out the dangers of adultery. Most of Solomon’s advice to his son in Proverbs 5-9 centers around the dangers of sexual sin. He acknowledges that adultery is seductive and enticing (“the lips of an adulteress drip honey,” 5:3) but that the result is deadly (“her steps lead straight to the grave,” 5:5).
But in Solomon’s exposition of the seventh commandment he also gives the positive aspect of the command: “Rejoice in the wife of your youth!” (v.18) and “Be captivated by her love!” (v.19). You have not kept this commandment when you merely abstain from illicit sexual relations outside your marriage, but the husband or wife is further obligated to faithfully pursue a love relationship with his or her spouse. Too many marriages have failed for lack of this pursuit.
Jesus, of course, also emphasized the depth of this commandment. In Matthew 5:27,28 he rebukes the teachers of the day for assuming that obedience to this command was achieved without consideration of the heart’s attitude. He affirmed that God’s original intent for this law was to include a lustful heart as an aspect of adultery, as a secret adultery of the mind. Not only is there adultery, there is adultery in one’s heart. And though the latter is not as bad as actual adultery, it is what leads to adultery if unchecked. It is a failure to pursue a love relationship with one’s spouse.
Though adultery is forgivable, the seriousness of this sin cannot be played down. It is serious enough to be a legitimate ground for divorce (Matthew 19:9). It is one sin that God explicitly says He will avenge (1 Thessalonians 4:6). Paul says, “Flee from sexual immorality!” because such a sin is a sin against one’s own body and our bodies are temples of the Holy Spirit (1 Corinthians 6:18,19).