Is it possible that the 120 believers who were gathered on Pentecost as described in Acts 2 were all clergy? At least 11 were apostles. If the Holy Spirit was OK with an apostle being chosen by means of winning a game of dice, there were at least 12 apostles (Matthias: Acts1:15-26).
What about the rest of them? How many were leaders? How many were simply people who loved Jesus and wanted to do whatever He said do, so they were obeying His instructions to wait for the Promise? How many people were not in the house, but received the Promise anyway, like Medad and Eldad in Numbers 11?
Peter told the 3000+ new believers that day that they needed to receive the Holy Spirit Who had filled him. Were they all clergy?
Every believer has an important ministry that is impossible to accomplish without supernatural power from the Holy Spirit making them able to want to do it and to be able to do it (Philippians 2:12-13). Only those who are willing to trade their old lives for His new life will step over the line into that place of being fruitful. The two classes of believers, if there are two, are obedient and disobedient, not clergy and laity.