It always begins in the heart

“You shall not commit adultery.” Exodus 20:14

One of the most infamous stories in Scripture regards adultery, where a powerful king of Israel, King David, seduces a beautiful woman, Bathsheba, while her husband is away at war (2 Sam. 11). In the opening few lines of text, we learn prior to their adultery, King David was not supposed to be home in his palace but out on the battlefield fighting on behalf of God’s kingdom. One evening while out for a walk, King David spots Bathsheba bathing and sends a messenger to inquire about her. The king’s servant reminds him that Bathsheba is the wife of Uriah the Hittite, one of his soldiers. Not dissuaded, David summons Bathsheba to his palace where they commit adultery, and she conceives.

Although King David was known to be a man after God’s own heart (1 Sam. 13:13–14), at the time that he committed adultery with Bathsheba, God was no longer the object of David’s greatest desires. His lusts were. He continued to pursue those lusts by inquiring about her, despite warnings, and looking at her merely as an object to be used to gratify his sinful desires.

We may be tempted to ask ourselves, “What does this commandment have to do with me?” while soothing ourselves with affirmations that at least we haven’t committed that sin. But Jesus, at the Sermon on the Mount in Matthew 5:27–28, brought radically new teaching that superseded the Old Testament Law and Prophets for believers by saying, “But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart.” Sexual sin, including lust, is a grievous affront to God and others, and the penalty is death.

Observation

Read Matthew 5:17–20; 27–30

In this context, how familiar would the audience Jesus was teaching have been with Moses’ law? How would Jesus’ words, effectually saying, “The Old Testament condemns adultery, but I say that lustful thoughts will condemn you to hell just the same,” have challenged their beliefs?
In Matthew 5:19, Jesus tells the crowd, whoever “relaxes,” or sets aside, the law and teaches others to do the same will be called the least in the kingdom. What is Jesus communicating about the standard of fulfilling the requirements of the law?
Matthew 5:28 used the word “already.” How does this word reveal one’s standing according to the law?
According to Romans 8:3–5, what is the hope for fulfilling the requirements of the law?

Interpretation

Marriage is a sacred covenant promise that is so significant that God describes it as a reflection of the great mystery of Jesus and his bride, the church, for whom he died (Eph. 5:32). Believers, by grace, are able to experience and give the world a picture of Christ’s love and devotion through marriage.

Christ’s commitment to his bride is so exhaustive that he loved us while we were yet unfaithful (Rom. 5:8) and gave up his life that we may live (Eph. 5:25). How does adultery misrepresent Jesus and his covenant with the church?
Jesus explicitly affirmed that marriage is a continuing, lasting commitment—“What therefore God has joined together, let not man separate” (Matt. 19:6; Mk. 10:9). How does God’s definition of marriage differ from that of our culture?
The Bible defines adultery as lust or sex outside the bounds of a legal and monogamous marriage (porneia) and warns us against those who would call evil good (Isa. 5:20). How is God’s goodness revealed in his commandment prohibiting adultery?
God intends oneness in marriage (Gen. 2:24) and love in our relationships (Mk. 12:28–31). What does Philippians 2:1 say is the source of our strength?

Application

Jesus’ sermon is not merely given to display humanity’s inability to obey God’s laws: it does that, but it also provokes our hearts to cry out to him for mercy. Believers who have been reconciled to God through Christ have constant cause for thanksgiving, as we have been given Christ’s perfect righteousness as our redemptive solution and can therefore boldly approach his throne!

In what ways have you minimized lust in your heart, fantasies in your mind, and technical “lines” you’ve crossed?
Thinking back to a time when you found yourself lusting after someone, whether an actual person or a fantasy, what was it that you were craving most?
How is comparing your spouse to another evidence of not treasuring God?
What lustful thoughts or adulterous actions do you need to confess to God? To others?
Read Colossians 1:13–14; 2:13–15. What comfort does the gospel bring in light of these confessions?