A lesson on what adultery is in God’s eyes, God’s good gift of sexual intimacy, and the importance of sexual purity in the life of the Christian. As we continue in our study through the Sermon on the Mount today, Jesus calls His audience to an ethic of sexual purity that goes beyond the body, extending to the thoughts and intentions of the heart. Sex is a wonderful thing; it is the physical representation of the joining together of one husband with one wife, a reflection of the mystery of Christ and the church being joined together as one. As such, it is designed by God exclusively for the covenantal relationship of marriage. But as with all good gifts, sinful man has a terrible propensity to abuse and distort it. In our day especially, the worldly concept of sex is utterly foreign and backwards in regards to God's design.

Nevertheless, adultery has plagued every generation, and is marked out as being particularly dangerous. So much so that Jesus employs some of the most vivid imagery of His entire earthly ministry to convey the necessity of cutting this sin off at the source. While every sin earns the sentence of death, adultery (among other sorts of sexual immorality) is notable in that we’re told unequivocally, the one who practices it will not inherent the kingdom of heaven. Unless one repents, this sin will most assuredly condemn them to hell. As we consider how many in our day, even within the visible church, contend with or otherwise yield to this sin, this should give us pause to consider the state of their souls as well as our own before the Lord.

Adultery encapsulates and compounds a multitude of sins: it is sexual perversion as well as idolatry, it is covetousness, it is theft, it reduces the image of God to an object for pleasure, it divides marriages, it sheers families apart, and it destroys souls; a Christian simply cannot flirt with it. No, it must be killed. The good news is that God not only calls us to radical purity, but that His grace enables us to take drastic measures to mortify our sins, including this one. Through faith in Christ we are not condemned but stand victorious, and standing in this victory by His grace, God will supply us with everything we need to keep us and to make us stand before Him blameless. As surely as God commands us to flee sexual immorality, with every temptation God supplies us with a way of escape. And Christ commands us that wherever temptation strikes, there you must cut it off. Remember that your body and soul altogether belong to the Lord; He paid the price to free you, so live not as a slave to sin, but to Christ.