“He that believeth on Me, as the scripture hath said, out of his belly shall flow rivers of living water. (But this spake He of the Spirit, which they that believe on Him should receive: for the Holy Ghost was not yet given; because that Jesus was not yet glorified)” (John 7:37-3837In the last day, that great day of the feast, Jesus stood and cried, saying, If any man thirst, let him come unto me, and drink. 38He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. (John 7:37‑38)).
Practically, although the Holy Spirit is presented here as power acting in blessing outside the one in whom He dwells, His presence in the believer is the fruit of a personal thirst, of need felt in the soul—need for which the soul had sought an answer in Christ. He who thirsts, thirsts for himself. The Holy Spirit in us, revealing Christ, becomes, by dwelling in us when we have believed, a river in us, and thus for others.
J. N. Darby, Synopsis, John 7