Acts 2:41 tells us that 3000 persons were added to the believers in Jerusalem following Peter’s sermon on the Day of Pentecost! Verse 42 adds:
And they were continually devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer.
We know from verse 47 that many more were added to their number in the days to come. Think about the spiritual earthquake that was occurring here. Large numbers of Jews were convinced and confessed that Jesus was indeed the promised Messiah, and they are now devoting themselves to the teaching of the apostles – mostly common men from Galilee who had no formal rabbinical training – instead of the teaching of the Jewish scribes and Pharisees. God the Holy Spirit was performing a supernatural work!
Moreover verses 42-47 tell us that an uncommon fellowship characterized by sacrifice for one another flourished among the new believers and was in part responsible for attracting more to their number. Remember that these Jews were not all regular residents of Jerusalem, but from every nation under heaven (vv. 5-11). And with time many of those people groups returned to their home territories. Some were likely responsible for establishing the church in places where the apostles never went, especially so-called Eastern & North-African churches, some of which remained very orthodox & strong long after the churches of Asia Minor and Europe began to lose their prophetic edge. So unknown even to the apostles in Acts 2, the mystery of the church, still to be revealed through Paul later in his letter to the Ephesians, was already being accomplished by the Spirit of God. Men and women from very different backgrounds were united by the Spirit of God in one body, the church, around the Word of God – the teaching of the apostles of Jesus Christ. This is God’s desire for us, the church in the 21st century: that we be one body united around the truth of God’s word, with a supernatural love that draws others to the Savior, and carry out the task of taking the gospel of Jesus Christ to every nation under heaven.