Part 13 of Kingdom Life
Text: Matthew 5:27-32
You can listen to this sermon here.
“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).
Strategies Are Not Enough
If you were to do a Google search for “How to be a better husband/wife?”, you’d find all sorts of strategies for being a better husband or wife (e.g., to be a better husband: (1) learn how to communicate; (2) be willing to compromise; (3) help your wife around the house). 
Strategies can be helpful, but they don’t address our fundamental problem: our sinful hearts. All sinful behaviours originate in the heart: “Out of the heart come evil thoughts [e.g., lust], murder, adultery, sexual immorality, theft, false witness, slander” (Matt. 15:19).
A Better Righteousness in Marriage
In Genesis 2, God “brought [the woman] to the man” (Gen. 2:22). And we are told, “Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh” (Gen. 2:24). A marriage is not merely a contract between two people. It’s “a sacred bond between husband and wife before God as a witness.” 
In our marriages, God wants us to have a righteousness that “exceeds that of the scribes and Pharisees” (i.e., a better righteousness). 
1. We must commit to the exclusivity of marriage, even in our thoughts.
Jesus says, “You have heard that it was said, ‘You shall not commit adultery’” (v. 27).  But Jesus declares that a husband or wife can be an adulterer even if he or she doesn’t commit the act of adultery. Adultery can happen in the heart: “But I say to you that everyone who looks at a woman with lustful intent  has already committed adultery with her in his heart” (vv. 27-28). 
Jesus wants us to take sin seriously: “If your right eye causes you to sin, tear it out and throw it away. For it is better that you lose one of your members than that your whole body be thrown into hell. And if your right hand causes you to sin, cut it off and throw it away. For it is better that you lose one of your members than that your whole body go into hell” (vv. 29-30). Jesus doesn’t want us to literally tear out our eyes and cut off our hands. He’s stressing that we need to do everything we can to avoid sin. 
2. We must commit to the permanence of marriage, even if our marriage doesn’t turn out the way we hoped it would.
Jesus says, “It was also said, ‘Whoever divorces his wife, let him give her a certificate of divorce’” (v. 31). According to Deuteronomy 24:1, a man was permitted to divorce his wife if he “found some indecency in her.” In Jesus’ day, the Jews debated the meaning of “indecency.”  Jesus’ interpretation was more strict than his contemporaries: “But I say to you that everyone who divorces his wife, except on the ground of sexual immorality, makes her commit adultery,  and whoever marries a divorced woman commits adultery” (v. 32). 
We should be less concerned with how we can get out of a marriage and more concerned with how we can stay in a marriage. When Jesus was asked about divorce in Matthew 19, he answered the question by going back to God’s original intention for marriage and said, “What therefore God has joined together, let not man separate” (Matt. 19:6). Today, Christians have different views on what Jesus meant by “sexual immorality,” but we can all agree on two things: (1) Jesus disapproves of easy divorce (“for any cause,” Matt. 19:3); (2) reconciliation should be the goal when marriage problems occur (cf. Matt. 5:23-26). While divorce is sometimes permitted, it’s never required.
Husbands and Wives Need Better Hearts
To be a better husband or wife, we need a better heart. Adultery begins in the heart with lust. Divorce was permitted because of the “hardness of heart[s]” (Matt. 19:8). How can a husband or wife get a better heart?
First, we need the Holy Spirit. “The fruit of the Spirit is love” (Gal. 5:22). The Spirit is given to all who put their faith in Christ. Then after we receive the Spirit, we need to continually remind ourselves of God’s love for us: “Husbands, love your wives, as Christ loved the church and gave himself up for her” (Eph. 5:25).
The essence of sin is self-centeredness, which is the source of all marriage problems. The opposite of self-centeredness is sacrificial love. In sacrificial love, Jesus gave up his life for us. If the Lord of the universe gave himself up for me, I should be willing to give myself up for my spouse.
 Andreas J. Kostenberger, God, Marriage, and Family, 73.
 As we have seen already in the Sermon on the Mount, Jesus wants his followers to be different.
 This is the seventh commandment (Exod. 20:14).
 Jesus is not saying it’s sinful to appreciate a woman’s physical beauty. Looking at a woman with “lustful intent” is having the desire to commit adultery with her.
 It could be said that lust is a violation of the tenth commandment because it says, “You shall not covet your neighbor’s wife” (Exod. 20:17). The Septuagint used the same Greek word for “covet” that Jesus uses for “lust.”
 Job said, “I have made a covenant with my eyes” (Job 31:1).
 The rabbinic school of Hillel believed that a man could divorce his wife for all sorts of trivial reasons (e.g., if she had bushy eyebrows).
 This doesn’t mean perpetual adultery.
 The apostle Paul also writes, “If the unbelieving partner separates, let it be so” (1 Cor. 7:15).