There was also a selection from psalm 104 where the psalmist talks about the "Spirit", a reading from Romans where Paul writes about the Spirit helping us in our weakness, and that part of the gospel of John where Jesus promises the Advocate, the Spirit of truth.
That set me to thinking. Did the Hebrews of the psalmist days and Jesus think of the same entity when they used the word "Spirit"? Christians profess belief in the Trinity, Father, Son, and Holy Spirit. Before Jesus arrived, did the Jews believe in a two-nity, Father and Spirit? Or was referring to the Spirit of God their way of thinking about how God can live and give life to the world?
Assuming that the Spirit in Acts is the same entity that Jesus promised would come, would Jesus have been surprised to see the effect of the Spirit? I suppose the speaking (or being heard) in tongues can be directly related to the charge Jesus gave the disciples, to teach all nations.
Then, I thought about today's Christians and how they regard the Spirit. Is it all the same?
One other thought I had. When everyone in Jerusalem could hear the disciples speak, each in his own language, did that represent the "undoing" of the results of the Tower of Babel, when the people tried to build something that would reach to God and God would have none of it. God tends to get testy in Genesis when humans aspire to god-likeness.
For those who know a lot more of all of this than I do, I'd love to hear your comments.