John 7:37-39 (NIV)
On the last and greatest day of the Feast, Jesus stood and said in a loud voice, “If anyone is thirsty, let him come to me and drink. Whoever believes in me, as the Scripture has said, streams of living water will flow from within him.” By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been glorified.