The church is always the congregation of the saints of God in any particular age. In the Bible the church is never a building. The congregation, that is the saints, can meet in a house, a garage, an office building, or a backyard and the group will still be God’s church. It is always a group of believers or saints.
Throughout history, the people and purpose of the church changes as God progressively revealed his plans and purposes. Here are some examples of churches the Bible describes:
The Church in the wilderness
For example, the Bible says that Moses was in the ‘church in the wilderness’ (Acts 7:38). Yet, back in the wilderness, Jesus had not yet died on the cross, nor had he instituted any new covenant, nor had He revealed the revelation of the mystery to Paul!
Moses was part of the group of God’s ‘chosen people’, the nation Israel, which was brought out of Egypt as God’s firstborn (Deut 7:6, Exodus 4:22, Exodus 19:4). This congregation of saints operated mostly out of the Old Mosaic Covenant, and was preoccupied with following God’s law to inherit the covenant blessings.
The Church in the Temple
Under the New Testament, there were devout and faithful Jewish believers that preached the gospel of the kingdom and that Jesus was the Son of God. These members of God’s church were not under God’s Old Covenant, but where subject to God’s New Covenant.
They were participants in the pouring out of God’s Holy Spirit at Pentecost, and were supernaturally able to obey the law of God as it was written in their hearts. Led by Peter, this congregation of saints was preparing to go into the kingdom. As such the Bible says that,
“And all that believed were together, and had all things common;  And sold their possessions and goods, and parted them to all men, as every man had need.  They, CONTINUING DAILY WITH ONE ACCORD IN THE TEMPLE, and breaking bread from house to house, did eat their meat with gladness and singleness of heart,  Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved. “ – Acts 2:44-47
The Church, the Body of Christ
For us in this dispensation, when we trust in the gospel and are saved, we are placed into the body of Christ, which is the church (1 Cor 12:13, Col 1:24).
“Now ye are the body of Christ, and members in particular.” – 1 Cor 12:27
Within this congregation of saints, Jesus Christ is the head and we are subject to him (Eph 5:23-32). We, who are saved, are each members of the congregation of the saints, the church, the Body of Christ.
You are the church
Members of the church, the Body of Christ, have a special standing distinct from the other churches. We do not go to a temple to worship God because we are the temple. Paul says,
“Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?” – 1 Cor 3:16
Paul exhorts the Ephesian elders to “feed the church of God, which he hath purchased with his own blood” (Acts 20:28).
The Bible says that he purchased YOU with a price, and that YOU are the temple of the Holy Ghost (1 Cor 6:19-20). Therefore, the church of God today is found in YOU! Wherever you are, the church is. That is why we are to glorify God in our body because God dwells in us, and so within us there is a ‘church service’ happening 24 hours a day! (Col 1:25, 1 Cor 3:16, Eph 3:17)
Now there are many members of the Body of Christ, the church today. So when many members of the church get together, that assembly or congregation of saints is also called a church.
When a group of saints gets together to praise God, study His word, and to build each other up, the Bible calls them a church. For example, Paul writes to the ‘church at Ephesus’, and the ‘church of Galatia’, and the ‘church at Corinth’.
However, each one of us becomes part of the church as we are placed into the Body of Christ.