Simeon hath declared how God at the first did visit the Gentiles, to take out of them a people for his name. Acts 15:14
Once again I am earning my reputation as one who could get shot at a Quaker picnic. I may seem to be misinterpreting what the church is and when it cane into being. But I think many churches and congregation members do just that.
A typical sermon or Sunday school lesson will be about the Gospels. Matthew is a favorite. A young Lutheran told me, "We stick to the Gospels." Sounds pious doesn't it? The Gospels are "safe".
Draw your moral lessons from the Sermon on the Mount. No one but Jesus ever kept it, but we must try. The hymn for such a lesson should be "To Dream the Impossible Dream". This sermon illustrates the perfect righteousness required by God. No blood of Christ in it, just the perfection required to please God. It should make people cling to the righteousness of Christ conferred by faith. When I hear, "I follow the Sermon on the Mount," I know I have a person who is not in touch with reality.
Those who limit their studies and behavior to the Gospels should attend synagogues. The Gospels were written for Israel. There is much of great value in them for the church, but they are not written about the church. It is not until we come to Acts chapter two that we see the beginning of the church.
A good Baptist told me that the narrative of Pentecost proves the church existed prior to that day. This, he said, was because that the Pentecost converts were said to be added to the church on that day ( Acts 2:47). I concede that the disciples were the core of the new church. But neither Jews nor Gentiles, other than the twelve, were in such a body.
Both Covenant people and Baptists like to make the church out as existing much earlier than it did. Covenant people claim the Jews were in the church during the Exodus, i.e., "the church in the wilderness". But "church" used alone merely means "a small group called out of a larger group". Unless "of God" is used, it does not refer to the church or anything necessarily holy.
Many Baptists date the origin of the church to John the Baptist, with Jesus as the first "convert". No kidding.
The church was a new body in the days of Acts. Jesus was calling out His bride, even as He is today.