Would it shock you to meet someone who self-identified as a “Racist Christian”? Or maybe a “Wife-Beating Christian”? Or maybe an “Adulterous Christian.” I think this would raise serious concerns for both Christians and non-Christians alike. There’s just something about a Christian identifying themselves with sin. It’s unsuitable.
See, Christians are no longer identified by their sinful inclinations, desires, or actions, they are identified by their union with Christ. Though Christians still struggle with indwelling sin, their union with Christ includes the indwelling presence and power of the Holy Spirit and a striving to turn from sin (not an identification with sin). There are no “Racist Christians,” “Wife-Beating Christians,” or “Adulterous Christians,” only Christians who, by the Spirit, are striving to put partiality, anger, and sexual immorality to death in their hearts and lives as the Holy Spirit brings true love to life in them.
What if a self-identifying “Racist Christian” shared with you, “I feel angst around Koreans” but then treated Koreans politely? Shouldn’t his angst be something he should put to death? What if the self-identifying “Wife-Beating Christian” said, “I don’t actually hit my wife, but I want to all the time.” Is his desire to abuse his wife good? Is it even neutral? And what if the self-identifying “Adulterous Christian” never cheated on her husband but regularly felt like it and fantasized about it? Would her feelings be sinful? In all these cases, feelings are sinful and displeasing to God. Yes, it is true, our emotions are corrupted by sin.
As Christians, we need to remember that sin corrupts our bodies, thoughts, choices, actions, and emotions; in other words, all of us. Sin corrupts our proclivities as well as our behaviors. We want things we shouldn’t want, and though we may not act on those wants, what our flesh wants is indeed evil. Such is the case with illicit sexual appetites, whether homosexual or heterosexual. There are no “Gay Christians,” only Christians who are, by the Spirit, living to put to death illicit sexual desires and immorality.
There is confusion in the Church today about what some call concupiscence. Webster’s 1828 defines concupiscence as:
Lust; unlawful or irregular desire of sexual pleasure. In a more general sense, the coveting of carnal things, or an irregular appetite for worldly good; inclination for unlawful enjoyments. 
So, when someone has an “inclination for unlawful enjoyments,” they desire that which is evil, and the inclination itself is evil. Jesus was clear about concupiscence. If a man has sex with a woman not his wife, it’s adultery. Adultery is evil. And yet, for Jesus, even when a man sexually desires a woman not his wife, his desire is adultery of the heart. Jesus said in his famous Sermon on the Mount, “everyone who looks at a woman with lustful intent has already committed adultery with her in his heart” (Matt. 5:28). How unfitting it would be for a Christian to self-identify as a “Lustful Christian.”
Think carefully about this. Joe is happily married. Joe sees a beautiful woman jog past. At first, Joe simply notices the woman. Okay. But, in a split second, Joe’s seeing turns into Joe’s sexual yearning for that woman. His heart beats faster. His mind fantasizes. Joe’s wife sits beside him in the car. She has no idea what’s going on inside her husband. Nothing has changed about Joe externally, but internally Joe is pursuing adultery in his heart. It happens in a matter of five seconds. Jesus condemns Joe’s illicit sexual inclination as adultery. Feeling the shame of his desire for adultery, should Joe simply self-identify as an “Adulterous Christian”?
Much of the confusion today regarding concupiscence is in reference to homosexual inclination and desire. Some argue the inclination and desire are not a problem as long as you don’t act on it, as long as you practice abstinence. This is mistaken. Whether it’s homosexual or heterosexual concupiscence, the point is that all illicit inclinations and desires are evil inclinations and desires that need to be put to death and replaced by sanctified inclinations and desires. Christians shouldn’t ever make peace with or accept their sinful proclivities; they ought to instead look to Christ with trust and hope in his ongoing sanctifying grace.
The Seventh Commandment is simple: “You shall not commit adultery.” The Seventh is much more than a prohibition of cheating on your spouse. Jesus said lustful intent is adultery of the heart. Ephesians 5:3–5 expresses the Seventh in broad terms:
But sexual immorality and all impurity or covetousness must not even be named among you, as is proper among saints. Let there be no filthiness nor foolish talk nor crude joking, which are out of place, but instead let there be thanksgiving. For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God.
All impurity is unbefitting of a Christian. Covetousness is a wicked desire, and it is improper for Christians. To self-identify as a “Covetous Christian” is slanderous.
We come today to Heidelberg 108 & 109. Heidelberg 108 asks: “What does the seventh commandment teach us?” It answers: “That all unchastity is cursed by God. We must therefore detest it from the heart and live chaste and disciplined lives, both within and outside of holy marriage.” Then, 109 asks, “Does God in this commandment forbid nothing more than adultery and similar shameful sins?” It’s asking whether the Seventh Commandment simply forbids behavioral sins. It answers:
Since we, body and soul, are temples of the Holy Spirit, it is God’s will that we keep ourselves pure and holy. Therefore He forbids all unchaste acts, gestures, words, thoughts, desires, and whatever may entice us to unchastity.
Scripture condemns more than behaviors, it condemns thoughts and desires as well. The Seventh addresses inclinations of the heart like covetousness, lust, sensuality, and feeling drawn to anything God considers evil. Heidelberg 5 says we are “inclined by nature to hate God and [our] neighbor.” Because of sin, our inclinations are wicked. This is why we need God’s redeeming grace in Christ.
What do we do when we realize we can’t change our sinful inclinations? We know we shouldn’t, but we desire wicked things. What do we do? We come to the Lord Jesus Christ who invites us who are troubled by concupiscence,
Come to me, all who labor and are heavy laden, and I will give you rest. Take my yoke upon you, and learn from me, for I am gentle and lowly in heart, and you will find rest for your souls. For my yoke is easy, and my burden is light. (Matt. 11:28–30)
We find our rest and hope in a crucified and risen Christ alone. He knows our plight. He died to give us freedom. He cares for us. When our desires are wicked, he offers rest to those who come to him for his rest.
Rather than trying to find rest and hope in self-justification, we ought to go to Christ who alone is our justification and who gives true rest to the justified. We will fight till we’re dead, but in the fight, our faithful Lord gives rest, comfort, and hope to our weary souls. What a loving Savior we serve.
 Webster’s Dictionary 1828, http://webstersdictionary1828.com/Dictionary/Concupiscence
This version of the Heidelberg Catechism is used by permission from the Standing Committee for the Publication of the Book of Praise of the Canadian Reformed Churches (CanRC). It has been lightly revised and edited. You can find the CanRC version printed in their Book of Praise: Anglo-Genevan Psalter (http://bookofpraise.ca/).
Scripture quotations are from the ESV® Bible (The Holy Bible, English Standard Version®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved. May not copy or download more than 500 consecutive verses of the ESV Bible or more than one half of any book of the ESV Bible.