Webster's Dictionary defines a society as "a group of persons regarded as forming a single community." Hence, while I would agree with the characterization of the Church as a society, I would dispute the right of this particular society to exclude its "unworthy" members.
Although Paul's use of the human body to talk about unity within the Church is clearly metaphorical, it does shed some important light on the subject at hand. (I Corinthians 12) Paul's comparison of the different parts of the body to the individual members within the church was intended to demonstrate to his audience that each person served a useful purpose within the "body of Christ." He wrote: "But now hath God set the members every one of them in the body, as it hath pleased him." (I Corinthians 12:18) My question is: If God is the One who has placed each individual within the Church, why would any one (two, three or more) of those individuals think that he/she/they had the right to remove someone from their midst?
Unity was a recurring theme in Paul's writings to the various churches he addressed. He wrote to the saints at Ephesus: "I therefore, the prisoner of the Lord, beseech you (that sounds more like a plea than a command) that ye walk worthy of the vocation wherewith ye are called, with all lowliness and meekness, with longsuffering
Paul continued: "There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all. But unto every one of us is given grace according to the measure of the gift of Christ." (Ephesians 4:4-7) Notice that? Even though there is one Church, Lord, God and faith, we each have different gifts that were given to us by God. In other words, we have to strive for unity despite our differences (and some of those differences, according to Paul, are God given).
Why different gifts and offices within the Church? "For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ: Till we all come in the unity of the faith and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fullness of Christ: That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive; but speaking the truth in love, may grow up into him in all things, which is the head, even Christ." (Ephesians 4:12-15)
So we don't all start out with the same level of knowledge, understanding and Spiritual gifts? And God is using those differences to help us to grow toward unity? In other words, God knows that there are differences among the people whom "He" has called and reaching understanding, maturity and unity is a process.
In fact, it seems to me that Paul is saying that part of the very purpose of the Church is to foster the development of that kind of understanding, maturity and unity among its members. It has to be developed. It cannot be imposed from the top down! And it certainly cannot be accomplished by throwing someone out of the congregation.
It is interesting to note, that similar notions regarding human authority within the Church led to disunity within the Church in the time of the apostles. John wrote about a man named Diotrephes who loved to be in a position of authority. (III John 9) This individual was apparently so full of himself that he wouldn't even acknowledge John! Moreover, anyone who dared to support John's ministry was cast out of the Church. (III John 10) John went on to instruct God's people not to follow such a bad example, but to instead look to God's goodness. (III John 11)
If you really think about it, the notion of casting someone out of the Church defies the logic of Christ's teaching as a whole. Didn't Christ picture himself as the Good Shepherd protecting the sheepfold? (John 10:11-16) Does it really make sense to cast one of the sheep outside of the sheepfold to be gobbled up by the roaring lion who is prowling around the perimeter seeking whom he may devour? (I Peter 5:8) It doesn't make any sense to me!
What is the conclusion of the matter? Does the Church have the authority to separate one of its members from Christ or his love?
Notice what Paul had to say about that: "Who shall lay any thing to the charge of God's elect? It is God that justifieth. Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us. Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword?...Nay, in all these thing we are more than conquerors through him that loved us. For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come. Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord." (Romans 8:33-39) Case closed!