I guess that the thing we have to realize about the Day of Pentecost, is that :
     1) It is a Jewish holiday
     2) It is a fullfilment of prophecy
                John 16:7-14; Joel 2:28-32
Not only is this evident by studying the scriptures and rightly dividing them, but Peter tells the believers there at Penetecost that this is a fullfilment of prophecy.

No where in prophecy is the church, the Body of Christ ever talked about.

And Paul states in Ephesians that God him the revelation of the dispensation of grace.  Eph. 3