The first use of the word “Church,” ecclesia in Greek, in the New Testament comes in the Gospel of St. Matthew, when Our Lord Jesus gives His approval of Peter’s confession of faith and promises, “On this rock (i.e. Peter’s declaration of faith) I will build My church” (Matt 16:18). So, He builds, and we cooperate with Him.

The Word “church” has three significances:
1.    The community of believers in Christ, “Great fear came upon the whole church…” (Acts 5:11).
2.    The clergy, “Moreover if your brother sins against you, go and tell him his fault between you and him alone… And if he refuses to hear them (two or three witnesses), till it to the church. But if he refused even to hear the church, let him be to you like a heathen and a tax collector. Assuredly, I say to you, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven” (Matt 18:15-18).
3.    The house of prayer, which is common usage, “In the church, I would rather speak five words with my understanding, that I may teach others also, than ten thousand words in a tongue” (1Cor 14:19; 1Tim. 3:15). Jacob called the place of his vision “Bethel” or the house of God, where God dwelt before him, saying, “How awesome is this place! This is none other than the house of God and this is the gate of heaven” (Gen 28:10-22)   
The Church is the Body of Christ
Having been joined to Christ and His church, the baptized believers live in unity as the one body of Christ. So the church is people energized by the Holy Spirit (Ephesians 4:7). St. Paul frequently described the church as the “body of Christ.” (Ephesians 1:23) He wrote, “For by one Spirit we were all baptized into one body… Now you are the body of Christ and individually members of it” (I Corinthians 12:13, 27), which means that the baptized believers are members of Christ’s body. He also wrote, “For no man ever hated his own flesh, but nourishes and cherishes it, just as the Lord does the church. For we are members of His body, of His flesh and of His body” (Ephesians 5:29, 30). So, we are the members of Jesus’ body, and “He is the head of the body, the church” (Colossians 1:18; cf. Ephesians 5:23, 24; Colossians 2:9, 10, 19).  

The metaphoric sense of the body of Christ is explained in more detail by St. Paul. He wrote that we received different gifts, but we still form one body. On other words, we are not all given the same gifts, but together we are equipped to do God’s will. “For as we have many members in one body, and all the members do not have the same function, so we, being many, are one body in Christ, and individually members of one another” (Romans 12:4-6). He also emphasized these gifts and their purpose when he wrote to the Ephesians that “There is one body.” He then wrote that “To each one of us grace was given according to the measure of Christ'’ gift . . . And He, Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for edifying the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ… speaking the truth in love, may grow up in all things into Him who is the head - Christ - from whom the whole body, joined and knit together by what every joint supplies, according to the effective working by which every part does its share, causes growth of the body for the edifying of itself in love” (Ephesians 4:4-16).
In the same context, St. Irenaeus, at the end of the second century, also looked at the Church as the “Body of the Great and glorified Christ,” who ascended to heaven.
The Church is the Pure Bride
Christ, the Bridegroom, betrothed the church, His bride, when His side was opened on the Cross. He purified and sanctified her to be pure without blemish as St. Paul says, “… Christ also loved the church and gave Himself for her, that He might sanctify and cleanse her with the washing of water by the word, that He might present her to Himself a glorious church, not having spot or wrinkle or any such thing, but that she should be holy and without blemish” (Ephesians 5:25-27, cf. 2Corinthians 11:2).
Since the church is His body and pure bride, she must be subject to the head, Christ, the Bridegroom, and keep His word. Being an apostolic and traditional, the Coptic Orthodox Church is faithful to keep the doctrines of faith without additions or omission. We should follow the divine teaching and implement the Biblical commandments without any deviation according to our will. It is not a democracy where the majority rules. We must remember that the majority is not always right. It is right only when each member closely follows Christ and His word.
The Believer is a Holy Temple
The believer, being born from the womb of the church, i.e. the baptismal font, became a holy temple, as St. Paul says, “Do you not know that you are the temple of God and that the Spirit of God dwells in you? If anyone defiles the temple of God, God will destroy him. For the temple of God is holy, which temple you are” (I Corinthians 3:16, 17; cf. 6:19; 2Corinthians 6:16).
Different Members in One Body
The church, being body of Christ, contains visible and invisible members. The visible members are the living believers of all nations. Christ did away with the barrier between the Jew and Gentile. “There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus” (Galatians 3:28). “The Gentiles are fellow heirs, of the same body, and partakers of His promise in Christ through the gospel” (Ephesians 3:6). “There is neither Greek nor Jew, circumcised nor uncircumcised, barbarian, Scythian, slave nor free, but Christ is all and in all” (Colossians 3:11).
The visible members are those who still battling here on earth, while the invisible members are those who victoriously finished their battle and started their heavenly life in the paradise, i.e. the saints (Revelation 7:9-17). Both members are united together with the bond of love; but the invisible members are more valuable and important than the visible ones. They interceded for us as they remember and honor them.   
We unite with the other members (visible and invisible) in one body of Christ, i.e. the church, because we all partake of the one bread, i.e. the Holy Communion, and we abide in Christ. As a result, God’s dwelling among His people in the past, whether in the Tabernacle or the Temple, has been replaced by His Incarnation. His body and blood are offered to us so that we may abide in Him and unite with Him in one body, as branches in the one Vine. The holy communion directs us to understand that God’s salvation comes to us in fellowship with our fellow men “For we, being many, are one bread and one body; for we all partake of that one bread” (1Cor 10:17).
St. Paul talks about unity and diversity in the one body saying, “For as the body and has many members, but all the members of that one body, being many, are one body, so also in Christ. For by one Spirit we were all baptized into one body- whether Jews or Greeks, whether slaves or free – and have all been made to drink into one Spirit. For in fact the body is not one member but many” (1Cor 12:12-14). He declared that the body, which consists of many members, different in their characteristics and gifts, but the body needs them all, and needs them all to work in harmony; and that all members are equal, valuable and needed. So he adds, “If the foot should say, ‘Because I am not a hand, I am not of the body,’ is it therefore not of the body? And if the ear should say, ‘Because I am not an eye, I am not of the body,’ is it therefore not of the body? If the whole body were an eye, where would be the hearing? If the whole were hearing, where would be the smelling?... And if they were all one member, where would the body be? But now indeed there are many members, yet one body” (1Cor 12:15-20). In the church, the body of Christ, we need each other, as he also says, “And the eye cannot say to the hand, ‘I have no need of you,’ nor again the head to the feet, ‘I have no need of you.’ No, much rather, those members of the body which seen to be weaker are necessary. And those members of the body which we think to be less honorable, on these we bestow greater honor; and our un-presentable parts have greater modesty, but our presentable parts have need, but God composed the body, having given greater honor to that part which lacks it, that there should be no schism in the body, but that the members should have the same care for one another” (1Cor 12:21-25).

So, Unity does not mean uniformity because each member is different and unique before God. Diversity in operation is:
1.    Based on ascent of the Son and descend of the Spirit ( Ephesians 4:8-10)
2.    Guided by specially gifted people (v. 11)
3.    For the sake of the maturity and stability of the body (v.v. 12-16)
4.    The head of the church is Christ (v.v. 14-16)
5.    The process of Christian growth requires our free-will commitment to walk in righteousness and Holiness (v.24)
6.    A change of life style is possible because of Christ, the original New Man (v. 24)
7.    In Christ, we are members of one another (v. 25)
The House of Prayers
The church is the house of God, the house of prayers for all nations and not for certain people only as Our Lord Jesus says, “My house shall be called a house of prayer for all nations…” (Mark 11:17). Being God’s house, it is naturally the dwelling place of God with His people, in them and for their interest. In the church, Christ meets the members of His Body in order that He may practice His divine and redeeming deed in their life. Thus ultimately, through His Holy Spirit, their new life is formed as a holy, living and active community, possessing the characteristics of their Head, without losing human features.

In other words, the church building provides an environment for the formation of this heavenly community surviving on earth. The believers live on a heavenly level as members of the body of the heavenly Christ, who sent His heavenly Holy Spirit to dwell in them. At the same time, they are human by nature and not isolated from the world. From every nation and every tongue they are gathered as a sanctified leaven, acting constantly for the renewal of the world so that it may enjoy the experience of the new life in Jesus Christ.

   Through such a concept of faith, the Church, being consecrated by the Holy Spirit, holds a distinctive sanctity in the believers’ eyes, for the Church Building is correlated with the holy Body of Christ as well as with the members of the Congregation. For this reason, on entering the church they kiss its steps, doors, icons and kneel before the sanctuary as if before God Himself. The Ecclesiastical history gives others countless examples of believers readily giving up their own life to secure churches, sacred vessels or church books from the hands of their persecutors. They acknowledged the close bond between such things and the Lord Himself. Any slackness towards them bears a direct dishonor to God. Consequently, nobody can claim the authority to sell them, even if it is he who has offered them in the first place.