John 7:38

ὁ πιστεύων … ζῶντος. [The nominative absolute is common.] No Scripture gives the words verbatim. Isaiah 58:11 has: “The Lord shall satisfy thy soul in drought: and thou shalt be like a watered garden, and like a spring of water whose waters fail not”. Cf. John 4:14. The words seem to intimate that the believer shall not only have his own thirst quenched, but shall be a source of new streams for the good of others (O. Holtzmann). A remarkably analogous saying is quoted by Schoettgen from the Talmud: “Quando homo se convertit ad Dominum suum, tanquam fons aquis vivis impletur, et fluenta ejus egrediuntur ad omnis generis homines et ad omnes tribus”. At the same time it is not easy to see the relevancy of the saying if this meaning be attached to it, and the saying of John 4:14 is so similar that it seems preferable to understand it in the same sense, of the inseparableness and inwardness of the living water. Those who advocate the other meaning can certainly find confirmation for their view in the explanation added by John.