John 7:37-39

New Matthew Bible

³⁷ In the last day, the great day of the feast, Jesus stood and cried out, saying, If anyone thirsts, let him come unto me and drink. ³⁸ He who believes on me, as says the scripture, out of his belly shall flow rivers of the water of life.

³⁹ He spoke this of the Spirit, which those who believed on him would receive.  For the Holy Spirit was not yet there, because Jesus was not yet glorified.