On the last day of the feast, the great day, Jesus stood up and cried out, “If anyone thirsts, let him come to me and drink. Whoever believes in me, as the Scripture has said, ‘Out of his heart will flow rivers of living water.’ ” Now this he said about the Spirit, whom those who believed in him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified.
On Sunday we remembered Pentecost, and the Gospel reading set for that day actually took place on another great feast day of Judaism: Tabernacles (or Booths or, if you speak Hebrew, Sukkot). It was one of the main events of the Jewish year on which, if they could, Jews would gather in Jerusalem for the seven day festival.
On the first day Zechariah 14:16-17 was read to the pilgrims:
Then everyone who survives of all the nations that have come against Jerusalem shall go up year after year to worship the King, the LORD of hosts, and to keep the Feast of Booths. And if any of the families of the earth do not go up to Jerusalem to worship the King, the LORD of hosts, there will be no rain on them.
Also associated with the feast was Isaiah 12:3, “with joy you will draw water from the wells of salvation”, and there was a great ceremony when water was poured at the base of the Altar. So it is that the festival was associated with life-giving rain, and the salvation offered by God who provided water to the Hebrews slaves as they wandered in the desert at the Exodus.
All this was going on when the crowds heard Jesus shout out “if anyone thirsts, let him come to me and drink”. It is through the Spirit that we gain life and salvation. It is through the Spirit that we receive sustenance.
So go to Christ and drink!