“It is actually reported that there is sexual immorality among you, and of a kind that is not tolerated even among pagans, for a man has his father's wife. And you are arrogant! Ought you not rather to mourn? Let him who has done this be removed from among you.
For though absent in body, I am present in spirit; and as if present, I have already pronounced judgment on the one who did such a thing.” --1 Corinthians 5:1-3 ESV
There is a place for believers judging those who practice sexual sin. In what context? This judgment is only towards Christians who are proud and unrepentant about their sexual sin. We aren't to judge non-Christians out in the world who have the same issue:
“I wrote to you in my letter not to associate with sexually immoral people—not at all meaning the sexually immoral of this world, or the greedy and swindlers, or idolaters, since then you would need to go out of the world. But now I am writing to you not to associate with anyone who bears the name of brother if he is guilty of sexual immorality or greed, or is an idolater, reviler, drunkard, or swindler—not even to eat with such a one. For what have I to do with judging outsiders? Is it not those inside the church whom you are to judge? God judges those outside. ‘Purge the evil person from among you.’" --1 Corinthians 5:9-13 ESV
Matthew 18 is all about dealing with sin in the church. It starts out with the teaching that greatness in the kingdom happens by becoming like an innocent, humble, teachable, trusting child in relationship with his/her Father. Then is a stern warning to whomever would cause a child of God (and/or perhaps an actual child) to sin by bringing temptation. If a church member brings temptation and sin into the church, we are commanded to cut that member off and throw “it” away; (1 Corinthians 12 refers to individual church members as a hand, foot, etc.).
Subsequently is a parable describing how just as a good shepherd leaves the ninety-nine sheep to go find the one lost sheep, it is God's desire that none of His little ones should perish. c.f. 2 Peter 3:9. The next passage deals with when a brother (fellow believer in Jesus) sins against you. First talk to that individual about his fault, and if he's unwilling to reconcile or deal with his offense, then bring a few more witnesses for accountability into the situation. If the brother is even then unwilling to repent of his error, get the church involved. If even then he's unwilling to change the way he thinks, he is to become an outcast (until he deals with himself and repents.)
If a believer is caught in a sin, he isn't to be immediately cast out from fellowship in the church, but restored gently back into right relationship with God and others (see Galatians 6:1ff). If he or she has a desire to change, to grow to maturity in Christ, and to live in Jesus’ victory over sin (which we already have the freedom, right, and authority to do), then we can help that brother or sister to do so through relationship, coaching, accountability, and together obeying the Word of God.
Having that member (foot, eye, hand, etc.) severed from fellowship is a last resort for one who has pridefully scorned all loving rebuke, correction, discipline, training in righteousness, and desire to change his/her ways. It is one thing to struggle with a sin yet desire and strive to change, and another thing to say, “There's nothing wrong with my attitude or behavior; I don't need to change and I don't care what [your interpretation of] the Bible says about this issue.”
“When you are assembled in the name of the Lord Jesus and my spirit is present, with the power of our Lord Jesus, you are to deliver this man to Satan for the destruction of the flesh, so that his spirit may be saved in the day of the Lord.” --1 Corinthians 5:4-5 ESV
What does this delivering the man over to Satan mean?
Matthew 18 concludes with the parable of the unforgiving servant:
“…Then his master summoned him and said to him, 'You wicked servant! I forgave you all that debt because you pleaded with me. And should not you have had mercy on your fellow servant, as I had mercy on you?' And in anger his master delivered him to the jailers, until he should pay all his debt. So also my heavenly Father will do to every one of you, if you do not forgive your brother from your heart.’" --Matthew 18:32-35 ESV
What do “the jailers” represent in this parable? May I suggest to you that they represent demons? How is that a reasonable, biblical conclusion?
We remember that the church was commanded to hand the unrepentant sexually immoral believer in 1 Corinthians 5 over to Satan (a broad term that also encapsulates the demons under his domain). The merciful purpose was “for the destruction of the flesh, so that his spirit may be saved in the day of the Lord.”
The proud, unrepentant (not willing to submit to God's Word or authority in his life) believer was excluded from fellowship in order that he could be reminded of how miserable life is apart from Christ. The thief (the demonic realm) would have free reign again to steal, kill, and destroy in his life. After he comes to his senses and desires to come clean and to get free from those inner demons or bad habits or unhealthy mindsets, then the church (ideally speaking) is waiting with open arms for his return, ready to throw him a party. See Luke 15:11ff and 2 Corinthians 2:5-11.
In order to be set free from demonic oppression—the jailers—you need to receive Jesus into your life as Master, for Jesus came to bring liberty to the captives. c.f. Luke 4:18. As the parable implies, you must forgive everybody who has ever hurt you. For no matter what they did to you, it is an incomparably tiny offense compared to the fact that we dishonored God—the infinitely glorious, perfect, authoritative, powerful King of the universe (even if we live in a democracy in the earthly, natural realm).
Since all authority in heaven and on earth has been given to Jesus, when we repent and forgive all who hurt us, then the jailers have no more legal right to imprison and torment us. Jesus then delivers us from the jailers (demons), having reconciled us to the Father through his blood. c.f. Romans 5:1; Colossians 1:13-14.
To find out more about overcoming sin and addictions in your life through a relationship with God, then I recommend “Part II” in my blog post “God Can Change Your DNA and Desires.”