Acts 2

Acts 2:1:
When the Day of Pentecost had fully come, they were all with one accord in one place 

​It is not clear with any certainty where this "one place" was. Tradition has it placed in the Upper Chamber where the first pre-Christians went to hold their religious meetings, however, vs 13 would indicate it would have had to been a place in view of the public

Acts 2:4:
And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance.

​This verse marks an important point in human history. This is the birth of the Christian Church. On that day the Divine society was constituted. Not until Pentecost were Christians a distinct corporate body.

Acts 2:42:
They were continually devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer. 

In this verse we have the fourfold activity of the church. The believers continued steadfastly in the teaching or doctrine of the apostles and fellowship, and in breaking of bread, and in prayers. It should be clear that these believers were not divided in any way. They had a single-mindedness to stand firm in what the apostles were teaching them and in doing that they partnered together to do so. In this they broke bread together and, of course, prayed together. There was a close communion with each other. This partnering together, this fellowship is second only to the foundational element of doctrine and teaching. It is crucial that Christians fellowship with one another. --Mark Ratliffe