How do we know the church was not established at Pentecost?

The assertion that the church began at Pentecost is unfounded since there is no scripture that supports this claim. Prior to Pentecost, Jesus had already gathered His disciples, gave them the Great Commission, and prepared them for the establishment of the church (Matthew 28:19-20). Important church functions such as preaching, baptism, and communal gatherings were already taking place. Thus, the idea that the church only became formalized after the Holy Spirit's descent does not align with the biblical account, as the church was already identified and active.