Summary: The message explores biblical reasons for open union with a local congregation.
“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. 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.
“Your boasting is not good. Do you not know that a little leaven leavens the whole lump? Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover lamb, has been sacrificed. Let us therefore celebrate the festival, not with the old leaven, the leaven of malice and evil, but with the unleavened bread of sincerity and truth.
“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.’” 
The Apostle to the Gentiles was not a particularly polished pastor by the criterion of contemporary congregational expectations. It is obvious that he wasn’t particularly concerned about feelings when those to whom he wrote were dishonouring the Master. What does shine through in all his missives is his deep commitment to speaking the truth in love. Unlike modern ecclesiastical politicians, Paul sought God’s glory, not man’s feelings of self-importance. In the text before us, it is difficult to believe that members of the Church of God in Corinth appreciated Paul airing their dirty laundry. But that laundry was dirty, and it was stinking, and the assembly had done nothing to clean up their act. Through his words, Paul emphasises the importance of church membership.
Scripture convincingly argues that a Christian must hold membership in a local congregation. Church membership is not necessary for salvation; however, membership in a local congregation is expected of all who seek a healthy relationship with the Saviour. One who professes Christ as Lord must honour Him by loving the church as much as Christ loves His Bride, and He loved her enough to sacrifice Himself for her. Remember Paul’s admonition to the elders of Ephesus, “Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the church of God, which He obtained with His own blood” [ACTS 20:28]. Amen!
Elsewhere, the Apostle admonishes those Christian men who are married, “Husbands, love your wives, as Christ loved the church and gave Himself up for her” [EPHESIANS 5:25]. Christ sacrificed Himself for His bride, the Church of the Living God. Because we are provided His model of sacrificial love for His Bride, we know that men are to willingly sacrifice themselves for their wives, modelling their love for their own wives after the love Christ exhibits for the church. If you are a Christian man and you are married, you are responsible to willingly give your life for the welfare of your wife. Your wife, men, is the priority for your life if Christ Jesus is King of your life.
In light of these statements, be assured that it would have been unimaginable for one who professed love for the Risen Lord of Glory in the early years of the Faith to refuse membership in a local congregation. This is the import of the words of the writer of the Letter to Hebrew Christians: “Let us consider how to stir up one another to love and good works, not neglecting to meet together, as is the habit of some, but encouraging one another, and all the more as you see the Day drawing near” [HEBREWS 10:24-25]. The emphasis of those verses is upon the voluntary commitment of each Christian to the welfare of those who shared this holy Faith.
I am fully aware that people have different reasons for holding membership in a congregation. Throughout the years of my service, I’ve known people who united with a congregation simply because it was convenient to do so. Many of these souls weren’t particularly engaged in the life of the Body, but they did join. Often, they would be absent from the services except at Christmas and Easter; but they were members, and they would be offended if it should be suggested otherwise. Others join a church out of obligation, or perhaps as a social necessity. Such people aren’t particularly concerned about investing their lives in the assembly, but they have what they believe is a good reason to be a member of the congregation.