The Lord was using the traditions of Pentecost (Shavuot in Hebrew) to communicate a message to his people.  The traditional reading for this feast is Exodus 19-20, which tells the story of what happened when God came down on Mount Sinai to give Moses the Ten Commandments in order to seal the covenant.  In that event, the whole mountain seemed consumed with fire.

^{Ex 19:18}Mount Sinai was covered with smoke, because the LORD descended on it in fire. The smoke billowed up from it like smoke from a furnace, the whole mountain trembled violently,

Just as the divine presence on Sinai was dramatically marked with fire, God was making his presence dramatically known at Pentecost with tongues of fire.  There is a great difference!  Instead of carving laws on tablets of stone, he was now enshrining the new covenant on the hearts of men through the power of the Holy Spirit.  On this specific day of Pentecost He gave his Spirit to seal a new covenant for the forgiveness of our sins, empowering us to live in communion with God.

^{Acts 2:1}When the day of Pentecost came, they were all together in one place.

²Suddenly a sound like the blowing of a violent wind came from heaven and filled the whole house where they were sitting.

³They saw what seemed to be tongues of fire that separated and came to rest on each of them.

Because it was this important, traditional holiday, Jerusalem was filled with visitors from many places, people who spoke in many different languages/tongues.  As the Holy Spirit enabled people to hear and understand Peter and the other apostles, in spite of the language differences, we can see how the Lord was facilitating and preparing for his gospel message to rapidly spread.

^{Acts 2:5}Now there were staying in Jerusalem God-fearing Jews from every nation under heaven.

⁶When they heard this sound, a crowd came together in bewilderment, because each one heard them speaking in his own language.

⁷Utterly amazed, they asked: “Are not all these men who are speaking Galileans?

⁸Then how is it that each of us hears them in his own native language?

⁹Parthians, Medes and Elamites; residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia,

¹⁰Phrygia and Pamphylia, Egypt and the parts of Libya near Cyrene; visitors from Rome

¹¹(both Jews and converts to Judaism); Cretans and Arabs—we hear them declaring the wonders of God in our own tongues!”

¹²Amazed and perplexed, they asked one another, “What does this mean?

We have now covered two events, the death of Stephen and the arrival of the Holy Spirit on Pentecost.  We see that God was using significant events to stimulate the new church.  In this manner, the first 40 years of the infant church accomplished tremendous growth and spread.  Across the Roman Empire in all of its major cities, the church was transformed from a tiny Jewish sect into a fellowship of many different peoples.

Blessings,

Larry