{Which} (hou). Genitive case by attraction from ho
(grammatical gender) to the case of pneumatos hagiou. We do not
have grammatical gender (only natural) in English. Hence here we
should say "whom," even if it does not go smoothly with
execheen (he poured out, second aorist active indicative of
ekche(935c)). The reference is to the great Pentecost ( Ac 2:33 ) as
foretold by Joel ( Joe 2:28 ). {Richly} (plousi(9373)). Then and to
each one in his own experience. See  Ro 10:12  1Ti 6:17 .