I think Josh made some good points about Pentecost and you can listen to them here if you so desire. But I found something interesting as I was investigating Pentecost. One of the passages where Moses talks about the establishment of the Feast in the Penteteuch was in Leviticus 23:15-22. What's really interesting to me is verse 22. Pentecost was about giving the first fruits of what the Israelites grew back to God and to take care of the priests. But in the establishment of this feast, God also makes provision for the poor.
22 " 'When you reap the harvest of your land, do not reap to the very edges of your field or gather the gleanings of your harvest. Leave them for the poor and for the foreigner residing among you. I am the LORD your God.' "Now, what's really interesting to me is how much this dovetails into the end of Acts 2, where we have the famous "communalism" verse in Acts 2:44
It's very easy for us to focus on the Holy Spirit and the speaking in tongues. If you grew up Church of Christ, you might have heard a lot about Acts 2:38, the "answer" to What Must I Do To Be Saved? But I think it's important for us to note that even in the establishment of the Feast of Pentecost, God had the poor in mind and when the Church came together, they kept the poor in mind. That should probably be something that we need to think about in our own congregational settings.
44 All the believers were together and had everything in common. 45 They sold property and possessions to give to anyone who had need. 46 Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, 47 praising God and enjoying the favor of all the people. And the Lord added to their number daily those who were being saved.