To the followers of Christ: On the last day of the Feast of Tabernacles, they traditionally celebrated by pouring out water from the temple.
"They fetched a golden vessel of water from the pool of Siloam, brought it into the temple with sound of trumpet and other ceremonies, and, upon the ascent to the altar, poured it out before the Lord with all possible expressions of joy." Matthew Henry.
It is thought that Jesus was referring to this when he said in John 7:37-38, "If any man thirst, let him come unto me, and drink. He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water."
At that time, the Holy Spirit had not been given because Jesus had not yet been glorified. His glorification came after he had died, rose again, and ascended to the right hand of the Father. It wasn't until Pentecost that the Holy Spirit was poured out. According to Matthew Henry, the gift of tongues was the flow of living water: "Now the time when the gospel should be propagated in the nations was not yet come, and therefore there was as yet no occasion for the gift of tongues, that river of living water." So when Peter preached, and everyone understood him, that's when the Gentiles believed.
And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance. And there were dwelling at Jerusalem J*ws, devout men, out of every nation under heaven. Acts 2:4-5
Every nation under heaven was there. Could this have been the fulfillment of "The Great Commission?" If not, it was the beginning, since people from every nation were there and could take that information back to their homeland to tell others.

















