You shall not commit adultery (Exodus 20:14).

Do not commit adultery. This command, like all the Commandments, seems so simple and straightforward. Yet, one look at the world around us–and even within the church–tells a different story. Like many of God’s commands, the church has often been guilty of treating only the symptoms without getting to the root cause.

The Spouse of Another

The word translated adultery here and in the Old Testament is the Hebrew word na’aph, which has the simple meaning “to commit adultery.” In Jewish and Ancient Near Eastern (ANE) societies of the time, adultery was defined as sexual relations by a married person with someone other than his or her spouse or fiancee/betrothed. (One who was betrothed was treated as though married for legal/moral purposes. Hence why the betrothal could only be broken by a certificate of divorce.)

While all ANE societies, including the Jews, took a dim view of adultery, there were some differences. Many non-Jewish societies spoke of adultery euphemistically as “the great sin.” (see Gen. 20:9, where Abimelech mentions this). However, when giving the law to His people, Yahweh specifically calls out adultery, and He never refers to it ‘discreetly.’ In addition, while adultery was always a crime against persons in the ANE world, for the Jews it was firstly a crime against God. (Note David’s statements in 2 Sam. 12:13; Psalm 51:4, expressing repentance toward the Lord for the sin of adultery.)

Adultery is to be distinguished from fornication (sexual relations between unmarried persons). While the penalty for adultery was death (Deut. 22:22), the penalty for seducing a virgin is the payment of a bride-price and an offer of marriage (Ex. 22:16-17). However, this should not be taken to mean fornication is a “lesser sin,” for the New Testament clearly teaches neither fornicators nor adulterers will see the kingdom of God (1 Cor. 6:9-10).

Adultery of the Heart

Like all sin, adultery begins in the heart. In our last post (“The Sin Behind Murder”), we discussed an important passage from the teaching of Jesus on sin.

For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. These are what defile a person. But to eat with unwashed hands does not defile anyone (Matt. 15:19-20).

As with murder, adultery begins in the heart. By the time one engages in the physical act of adultery, he or she has already committed adultery in the heart. Jesus made this clear when He said,

You have heard that it was said, ‘You shall not commit adultery.’ But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart (Matt. 5:27-28).

To commit adultery is to break a covenant relationship and seek after another. And since marriage is to be a representation of God and His covenantal love for His people, adultery, like murder, is an attack on the very image of God. The root issue behind adultery, then, is turning the heart toward another. This is reflected over and over in the Old Testament, as God calls Israel to return to Him.

As we know, Israel’s history was marked by constantly turning from Yahweh to other gods. The Lord called this adultery (Jer. 3:6-10). He had entered into a covenant with Israel, and they had broken the covenant (time and time again) and turned to others. This leads to an important point in our discussion of adultery.

To commit physical adultery, one first commits adultery in the heart. One who commits adultery with another person has already committed spiritual adultery against the Lord.

Why is this true? It is true because when we turn away from God’s design and willingly break His commandments, we turn away from Him. We say to Him, “You are not enough; your Word is not enough, I’m going to do things my own way.”

How does one avoid adultery? By keeping his heart turned toward the Lord, and his/her spouse. Love is fundamentally neither an emotion nor a choice of the will. Love is firstly a disposition of the heart. When my heart is turned toward the Lord, then the rest of me will follow. When my heart is turned toward my spouse, then the rest of me will follow. When my heart begins to turn away or draw back, again, the rest of me will follow.

As we live out the Great Commandments, we will find our hearts fixed on the Lord and His presence and plan for our lives, and thus avoid the great sin.

You shall love the Lord your God with all your heart and with all your soul and with all your mind and with all your strength. . . . You shall love your neighbor as yourself (Mark 12:30-31).