Holy Spirit baptism was a unique evidence of God’s acceptance of two new churches (Acts 2; 10). It is possible that “Holy Spirit baptism” is an umbrella term that covers both the supernatural experience of Acts 2 & 10 as well as water immersion, but the two are clearly different. The connection is natural enough from the OT where the Holy Spirit is metaphorically equated with water: “I will pour out of my Spirit on all people …” (Joel 2:28; cf. Isa 32:15; 44:3–4; Ezek 36:25–27; see also 1QS 3:7–9;