An International Center for Fellowship and Learning

The Sermon on the Mount Pt. 1 – Lesson 9: Adultery

“Drink waters out of thine own cistern, and running waters out of thine own well. Let thy fountain be blessed: and rejoice with the wife of thy youth.” —Proverbs 5:15, 18

Scripture Reading: Matthew 5:27-30; Proverbs 5:1-20


The idea that we can “look but not touch” someone of the opposite sex is commonplace in our society. Lusting and fantasizing over someone else is not only acceptable, we’ve actually begun to encourage it. Yet, Christ came to do away with this “look-but-don’t-touch” rule. If we’ve done it in our heart, then we’ve sinned.

Adultery not only speaks to a specific act or sinful imagination, it speaks to our desires and motivations. If a single person sees in most people of the opposite sex a “potential spouse” rather than seeing him or her as a child of God, then their motives aren’t pure—they’re selfish and self-serving. If a husband finds enjoyment from spending time with a particular woman at the office more than his wife, then he’s setting himself up for adultery. If a wife confides in a man other than her husband, she’s priming herself for a sexual fall.

The true test of our heart and motivation is what we would do if we were sure no one would find out. How easy it is to stay “pure” when we’re surrounded by others who think adultery is wrong. Nevertheless, put someone with a heart full of lust in a tempting circumstance and we have a recipe for disaster. If our heart isn’t pure, then no matter how much we restrain our fleshly desires, we’ll never stop committing adultery.

Christ came not only to reveal that adultery of the heart was wrong, but also what we need to do about it. “Cut off your hand and pluck out your eye,” He said, “It’s better to lose one member than be cast into hell.” This wasn’t meant literally but spiritually. If a source of temptation continually causes us to stumble, we need to get rid of it. It doesn’t matter if it’s our diet, the T.V., a hobby, a particular character trait, or anything else—we’ve got to get rid of it. If we don’t, then we’re in danger of not entering the Kingdom.

Lesson Questions:

  1. Why is it important to recognize that the act of adultery begins in the heart and mind? Ephesians 4:22-24; Matthew 7:17-19; 12:34.
  2. What does 1 Corinthians 6:15-20 teach regarding sexual purity? Consider Proverbs 5:15-23. Why is it important to recognize that sexual purity isn’t simply ridding our lives of impure thoughts, words, and actions?
  3. Why is adultery the only sin in which someone can sin against their own body? 1 Corinthians 6:17-19; Proverbs 6:30-33; 7:22-23.
  4. Does this passage teach that adultery of the heart was acceptable before Christ’s earthly ministry? Proverbs 6:23-25; 2 Samuel 11:2-4; 13:1-14.
  5. What is the intent of “plucking” your eye out, and “cutting off” your hand? Romans 13:14; 8:13; Colossians 3:5. Is this an issue of sacrificing our desire for the will of God? What practical outworking of this principle should we see in our lives?
  6. Does Christ’s emphasis on the spirit of the law indicate anything about the state of the Jewish heart during His ministry? Matthew 3:7-12; John 8:39.
  7. How would Christ’s application of this passage been seen as a practical fulfillment of Jeremiah 31:31-34?

Life Application:

Over the next week, take a personal. inventory and honestly determine if you struggle with sexual impurity. If so, make a detailed list of how, when, where, and why you’re tempted. Study biblical passages which deal directly with these areas, and write down specific words, thoughts, and actions you’ll take when confronting sexual temptation. If possible, make yourself accountable to another mature Christian.