1 Corinthians 5 & 6

And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God. (1 Corinthians 6:11)

The fifth chapter of of 1st Corinthians opens with Paul addressing sexual immorality in the Corinthian Church. There was a man there who had taken his father's wife. Either his father had died or the woman may have been his step-mother, but Paul is outraged because, even the Greco-Roman culture of that time accepted as norm, a wide array of immoral activities, they censured this kind of incest. (1) Paul states how is it that you are boasting that you follow this person, or that person, when you have a member of the Church who is involved in this type of immorality. Paul says they should not be boasting, should not be arrogant, but should be in mourning. Paul condemns this relationship to the point that he tells the Corinthian Church to deliver this man over to Satan  for the destruction of the flesh, so that his spirit may be saved in the day of the Lord.  Being delivered over to Satan means that they should expel this member, cast him out of the Church, which is the domain of Jesus Christ and send him back into the world, which is the domain of Satan. It means that you are not to engage in any Church-related activities with this individual. This is for the destruction of the flesh. This means that the idea behind this excommunication is to ultimately win the man back as a brother, that he should give up this incestuous relationship and come back into the Church, and be accepted back in (2 Corinthians tells of hie return).  Paul warns the Church that a little leaven (sin) makes the whole lump sinful. This shows the seriousness of the Body of Christ, of the local Church, it should be guarded, ultimately God is guarding the Church, but the local Pastor and Elders also have that responsibility, and the membership as well. Open sin within the Church, stains it, it damages the spirit of the Church, and if allowed to continue and grow unabated, that local Church can become apostate and become a synagogue of Satan and not a part of the Body of Christ. That's why Paul tells the Corinthians to worship, live, and seek the unleavened bread of sincerity and truth.

Paul tells them that he wanted them to not associate with sexually immoral people - he says he is not talking about the people in the world but the people in the Church. They should also avoid those who are greedy, swindlers, idolaters, or a drunkard. This is concerning people who are in the Church, who claim to be Christians. Paul says to purge the evil person from among you.  A person who continues to live an immoral life as a member of the Church, the Body of Christ - has missed the gospel. The gospel that this person believes is not the Gospel of God, it is a gospel of the culture. That believes it is OK to do what the world does and be a member of Christ also. This person does not understand the Holiness of God and the sinfulness of man. Paul says to purge the evil person from among you. The Old Testament Saints would cast the evil person outside of the camp, the New Testament Church has that same authority, most do not utilize it. Some do, however. This mixture of sin and Christ in the Church is missing the mark, it is evil and Christ will separate the sheep from the goats on the last day. We should take the warnings of Scripture seriously and adjust ourselves accordingly.

in chapter six, Paul discusses the loss of the Church by making lawsuits against each other. He wants them to know that the Church is a family and it should be able to handle its problems in house. The Church is suppose to be in submission to Christ and in a sense to each other, as member of the Body of Christ. Paul even says to take wrong at the hand of another part of the Body of Christ, rather than filing a lawsuit against another. To do so is already a defeat. For it shows that we are not living in obedience to Christ in the first place if we have to sue each other. 

Paul comes to a main point next. No matter where you go in the New Testament you are going to hear about the doctrine of Sanctification. According to the Westminster Shorter Catechism (Q. 35)
sanctification is "the work of God's free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness." It is a continuing change worked by God in us, freeing us from sinful habits and forming in us Christlike affections, dispositions, and virtue. (2)  Paul says "Do not be deceived" neither the sexually immoral, nor idolaters, nor adulterers, nor men who practice homosexuality, nor thieves, nor the greedy, nor drunkards, nor revilers, nor swindlers will inherit the kingdom of God. And then he says and such were some of you.  The Church of the Lord Jesus Christ is for sinners, it is not for those who do not think they are sinners, it is for people who the Spirit of God has come to and given them spiritual eyes to see that they are sinners. If you are not a sinners you have no need of a Savior. Paul says that all of these sins will keep you out of the kingdom of God, but some of these Corinthians saints did some of those sins, yet Paul called them the Church of God that is in Corinth; those sanctified in Christ Jesus, called to be saints, in the first chapter. The reason they are saints is the same reason we Christians today are saints. Christians who may have done some of those sins that God is going to keep out of heaven. Christ is our sanctification, Christ is our redemption. We could have committed all of those sins, but if the Spirit of Grace has come, He has broken our hearts concerning our sins, and we are sorry for our sins, we do not wish to sin against the One who has saved us. We understand the depth of lostness we were in. We understand the unbridgeable gap that separates us because of the holiness of God and our sin. We agree with Paul that the body is not meant for sexually immorality, but for the Lord, and the Lord for the body. Christ Jesus died for those sins and God raised the Lord and will also raise us up by His power.

Paul asks the Corinthians as well as us today; "Do you not know that your bodies are members of Christ? Shall I then take the members of Christ and make them members of a prostitute? Never!
The sexual immoral person sins against his own body. Your body is the temple of the Holy Spirit within you, whom you have from God. Paul explains true Christianity to the Corinthian believers and to us who are believers today. He ends chapter six with these words that are the heart of Christianity. You are not your own.We have been bought with a price. So glorify God in your body. God has purchased us - Christ's obedient life, and death and receiving God's wrath on the cross was the price paid to God. The Spirit of God in us is showing us the love that was involved in this, He is showing us the evil of our sin in causing this price to have been paid, He is showing us in His Word, His sovereign will and leading us glorify our Eternal Father with all that is in us and with our body.

Blessing.