“Did you receive the Holy Spirit when you believed?” (v2). The disciples Paul met in Ephesus had been following the teachings of John the Baptist, which led them to a “baptism of repentance” as preparation for the Messiah (v3-4). Paul told them that they could have more – not just turning away from sin, but also receiving God’s own Spirit through faith in the life, death, and resurrection of Jesus. The “Holy Spirit came on them,” and they spoke in tongues and prophesied.
“Into what then were you baptized?” (v3). Through Christ, God saves us from sin so that we can be reborn as His children, filled with His Spirit, experiencing new life.