John 7:37-39

37The last day of the festival was the most important day. On that day, Jesus stood up and he spoke with a loud voice. He said, ‘If anyone is thirsty, he should come to me so that he may drink.

38It says in the Bible, “God will cause streams of water to pour out from anyone who believes in me. Water that gives life will come out from inside that person.” ’

39Jesus was speaking about God's Spirit, who would come to people some time after that. Those people who believed in Jesus would receive God's Spirit at that later time. But God had not yet given his Spirit to people, because he had not yet raised Jesus back up to heaven.