As for other matters, brothers and sisters, we instructed you how to live in order to please God, as in fact you are living. Now we ask you and urge you in the Lord Jesus to do this more and more. For you know what instructions we gave you by the authority of the Lord Jesus. It is God’s will that you should be sanctified: that you should avoid sexual immorality; that each of you should learn to control your own body in a way that is holy and honorable, not in passionate lust like the pagans, who do not know God; and that in this matter no one should wrong or take advantage of a brother or sister. The Lord will punish all those who commit such sins, as we told you and warned you before. For God did not call us to be impure, but to live a holy life. Therefore, anyone who rejects this instruction does not reject a human being but God, the very God who gives you his Holy Spirit. (1 Thessalonians 4:1-8 NIV)
In his first part of his first letter to the Thessalonians, the Apostle Paul urges them to "walk in a manner worthy of God" (Chapter 2, verse 12). In the middle section of the letter, Paul is forthright with them that temptations have come, like the temptations of lust and sexual immorality. It is perhaps an understatement to say that our culture today is rampant with the temptations of lust and sexual immorality, isn't it? Then at the end of the letter, Paul lays out the hope that Jesus is coming to right every wrong and set up His perfect Kingdom.
Even as Paul lifts up temptation, he clearly states God's will for our lives: It is God’s will that you should be sanctified. (verse 3)
To be sanctified is to be made holy. The Greek word here is hagiosmos, and it does not mean sinless perfection in the way we usually think of holiness. It's meaning is rather being set apart for God's use. To be sanctified is to be made completely all that God desires us to be as creatures made in His image. To be set apart for Him means to be completely His, so that His desires become our desires and His holiness marks our lives.
Paul equates being sanctified with avoiding sexual temptation and sin. It is God’s will that you should be sanctified: that you should avoid sexual immorality. The Greek word here is porneias, from which we get the word pornography. It's most direct translation is fornication, which rightfully means sexual immorality. This is the opposite of sexual purity.
In scripture, sexual purity is expressed in two ways: abstinence (or chastity) in singleness, and faithfulness (not adultery) in marriage. Sex is a great thing! It is a holy gift of intimacy given by God to ensure the survival of humanity by making babies. But it is intended to be more than simple pleasure. It is intended to bond a man and a woman together in the kind of intimacy in marriage where we walk through life together "naked and not ashamed". (Genesis 2:25)
“You have heard that it was said, ‘You shall not commit adultery.’ But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart." (Matthew 5:27-28 NIV)
Jesus takes sexual immorality to the core of our hearts. Sin is always first a heart issue, then a behavior issue. The heart problem is lust. It is unbridled desire. It is selfish, out-of-control desire. And it must be noted that lust is not just a guy issue, although men struggle with lust perhaps more than women because we are wired with a strong sexual desire that is stimulated visually.
This, in my opinion, is one of the biggest problems with pornography. It is spiritual adultery. It is lusting for a woman (or a man) we are not married to. It is unbridled lust that carries the soul into utter selfishness, seeking the pleasure of sex with no relationship or commitment. A man who is addicted to pornography has a real struggle seeing women as daughters of God when the instinctive response is to see them as objects of sexual desire. Besides being cancer in the soul of the viewer, the sad fact is that most of the women who perform in pornography are being trafficked. Pornography is far from a harmless, victimless pastime, and it breaks God's heart when we participate in it.
Let it also be noted that we can lust after other things besides sex. We can lust after power. We can lust for comfort. We can have unbridled desire for possessions and money. It is all still a heart issue.
The crux of it in 1 Thessalonians 4 seems to me to be verse 7: For God did not call us to be impure, but to live a holy life. How can God expect this of us? He gives us Himself. He gives us His Holy Spirit to indwell us and sanctify us in holy love. God makes all the difference.
Flee from sexual immorality. All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body. Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; you were bought at a price. Therefore honor God with your bodies. (1 Corinthians 6:18-20 NIV)
With the Holy Spirit fully indwelling us, we can honor God with our bodies and turn from unbridled sexual desire to proper, holy desire for one another in marriage. The accusation has been made that we Christians seem to be all hung up on sex. In a sense, it is the hedonistic culture we live in that is all hung up on sex. And in another sense, we are all hung up on sex because "All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body."
So God's strategy for dealing with sin in our hearts is to root it out and replace it with holy things - with Godly virtues. The virtue that replaces lust is chastity. Chastity is the gift of self-control. To be chaste is to control one's desires and order them into a life that honors God and His design for us as bearers of His image. This self-control is not just clenching our teeth and trying hard to control lust in our hearts. It is receiving the Presence of the Holy Spirit, who grows the fruit of the Spirit in our lives, which includes the fruit (the gracious gift) of Godly self-control.
But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, gentleness and self-control. Against such things there is no law. (Galatians 5:18-20 NIV)
I want to live a holy life, but I cannot do so in my own power because of my fallen sin nature. I need the Holy Spirit to live a holy life. I need the Holy Spirit to control passion and live a chaste life, with all my passions ordered within the will and purposes of God. Come, Holy Spirit. Sanctify me in holy love and make my life all that you want it to be.