A church is the people described in Acts 2:41-47. They have gladly received the word of God, been baptized, and now they meet together, learning more of the faith, joining together in the Lord’s supper and in prayer, looking to each other’s needs, having joy in their hearts and praising God together.
A church is the people described in 1 Cor 1:2-8. They have been set apart in Christ, called in holiness, have received undeserved favour and peace from God; their knowledge of God and their witness to Him comes from the Holy Spirit, who has given them corporately all the gifts they need to function as a church, as they eagerly await the return of their Lord who will preserve them in Him until that day.
In other words, a church is Christians.
Did the Church exist in the Old Testament? Well, yes and no. In the sense that the Church is the people of God, then, yes. There were true believers in Christ before Christ. But they did not assemble together as believers. Israel was not the Church. Presbyterians point to Acts 7:38, which describes Israel as the
ekklesia in the wilderness, but all that this means is that the Israelites assembled together as a body before the Tabernacle. But Israel was a ‘mixed multitude’; some indeed were truly the Lord’s people, but the large majority knew nothing of the Lord experientially (e.g. Isaiah 1:9; Jeremiah 5:1-2 ). Israel by no means met the definitions of a church that we have seen above.
In the first appearance of
ekklesia in the Bible, the Lord Jesus declared,
‘I will build My church’ (Matt 16:18 ). The tense is future. Our Lord laid the foundations of His Church during His time on earth. Ephesians 2:20 tells us that this foundation is that of the
‘apostles and prophets’, and whether we believe that the prophets were of the Old or New Testament, clearly there were no apostles before the time of Christ. If there was a church in Old Testament times, then it can have had only half a foundation! In fact it is clear that Paul is speaking of the New Testament prophets since he couples apostles and prophets a little later in the letter (Eph 4:11 ) in a context that is obviously New Testament.
The Lord Jesus is continuing to build her even at this present time (Ephesians 2:21-22 ); she is His Church, His bride; He has purchased her with His own blood and she is a chaste virgin. As it is written,
‘In that day there shall no longer be a Canaanite in the house of the Lord of Hosts’ (Zech 14:21 ). It is the duty of the leadership of each individual church to seek to make the assembly in its charge as pure as possible (2 Cor 11:2 ).
The Church is composed of those who have come out of the world to join it. They are no longer what they were (Ephesians 5:8 ). Peter speaks of them as
‘sojourners and pilgrims’ (1 Peter 2:11 ). Therefore Abraham would have fitted into it rather well.
[Taken from my blog article
What is a Church? However, the article was written some years ago and I'm not sure I would write everything exactly the same today]