Who did the Holy Spirit come upon?

 Saint John Chrysostom

Was it upon the twelve that it [the Holy Spirit] came? Not so; but upon the hundred and twenty. For Peter would not have quoted to no purpose the testimony of the prophet, saying, 'And it shall come to pass in the last days, saith the Lord God, I will pour out of My Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams' (Joel 2:28). 'And they were all filled with the Holy Spirit.' For, that the effect may not be to frighten only, therefore it is both 'with the Holy Spirit, and with fire. And began to speak with other tongues, as the Spirit gave them utterance' (Mt. 3:11).