Welcome to the first of a new (hopefully weekly) series of short commentaries on lectionary readings. This is a great story that is rich with symbolism and imagery - it also features some excellent examples of why it's not necessary to understand the text literally for it to be meaningful.
The word 'pentecost' (from the Greek Penthkosth) refers to the 50th day after Jesus' resurrection. In the tradition of Luke/Acts, this is the symbolic timing for the outpouring of the Holy Spirit. Of course in John's gospel, Jesus breathes the Holy Spirit into the disciples on Easter Sunday. The timing is not the issue - this is about theology (or maybe pneumatology) not chronology. If the number 7 symbolises perfection in the ancient Hebrew world, then something that could follow 7x7 would have to be very special indeed. Luke has already referenced the notion of the Jubilee, a 50 year symbol of liberation, in Jesus' first sermon (Luke 4:16-21). Now he is going to take that same symbol and apply it through the disciples to the rest of us.
In the Jewish tradition, 50 days after Passover is the festival called (hag sabuôt) the ‘Feast of Weeks’ which after the Exile developed an association with the covenant of Moses and a legend involving 70 'tongues of fire' - again a symbolic number representing every nation of the world. Reading this story through the lens of Hebrew history is critical to understanding what's going on here. This isn't about a new, secret, divine language - it's about reversing the curse invoked in Genesis 11. Where the sin of hubris separates humans and confounds communication, the Spirit of Jesus brings people together in a radical new community of compassion.
A final thought: The quotation from Joel emphasises the universality of God's new reign – it's not just men and women, not just old and young, but even slaves are included! In fact, scholars have suggested that early Christianity was disproportionately represented amongst the slave class. Why? Because they understood that the gospel message was essentially about liberation.
Till next time...