What is Spirit-Baptism?

Calvin's Commentary on Acts at 10:2-4,22,25,44.

9. At 10:44, while Peter was still speaking these words, "the Holy Spirit fell on all of them (epesen). Then, 10:45, the Hebrew Christians there, witnessing this, were astonished –because the gift of the Holy Ghost had been poured out (ekkechutai) also on the Gentiles. "For" [10:46] the Hebrew Christians "kept on hearing" (eekouon) the Gentiles "continuing to speak in languages and continuing to magnify God" (lalountoon and megalunontoon).

10. Acts 10:47. "Then Peter answered: 'Nobody is able to keep on withholding (meeti dunatai koolusai) the water, so that these should not be baptized — [these] who have received (elabon) the Holy Spirit even just like us (hoos kai heemeis)!' So he commanded them to be baptized in the Name of the Lord." By whom? Apparently by Ministers of the Word and Sacraments, who had come there, together with Peter. Acts 10:23,45,48 & 11:12.