How Many Were Filled with the Holy Spirit in Acts 2:1-4?

Acts 2:1-4 describes a group of people who were filled with the Holy Spirit on the day of Pentecost. The effect of the Holy Spirit filling them was that they spoke in languages that they had not previously learned. Additionally, this group had tongues of fire resting on them, serving as a visual distinction that set this first group apart in Acts 2:1-4. Who was in this group, contextually?

This group is grammatically linked to the twelve apostles, including Matthias, since the pronoun “they” in Acts 2:1 refers back to the most recently identified group, namely the twelve apostles in Acts 1:26. Furthermore, those who heard this group speak identified all of them as Galileans, which was a distinguishing characteristic of the twelve who were closest to Jesus (Luke 22:59). Finally, when Peter acted as the spokesman for this group, Luke identified the number included in the group as twelve: Peter, plus the eleven (Acts 2:14).

Some have suggested that all 120 people mentioned in Acts 1:15 were part of the group who were filled with the Holy Spirit, who spoke in languages they had not learned, and who had tongues of fire resting on them. However, the grammatical connection to the twelve, the crowd’s description of them all as Galileans, and the numerical limitation provided by Luke in Acts 2:14 firmly disprove any notion that all 120 were part of that unique group in Acts 2:1-4. Instead, what the Scriptures present is exactly what Jesus prophesied: the twelve apostles received power when the Holy Spirit came upon them in Jerusalem, and they became witnesses of Jesus, testifying in Jerusalem, then in all Judea and Samaria, and even to the end of the earth (Acts 1:8).