John 7:37-39

Then on the most important day of the feast, the last day, Jesus stood and shouted out to the crowds—“All you thirsty ones, come to me! Come to me and drink! Believe in me so that rivers of living water will burst out from within you, flowing from your innermost being, just like the Scripture says!” Jesus was prophesying about the Holy Spirit that believers were being prepared to receive. But the Holy Spirit had not yet been poured out upon them, because Jesus had not yet been unveiled in his full splendor.