7:37-38 And on the great day, which is the last of the feast, Yeshua stood and cried out and said, If anyone thirsts, let him come to me and drink. Whoever believes in me, as the Scriptures have said, rivers of water of life will flow from his belly. –
The occasion is the last great day of Sukkot (Jn. 7:2) and the setting appears to be the water libation ceremony at the Temple. A priest had a flask of gold filled with water and another has a flask of gold filled with wine. There were two silver bowls perforated with holes like a narrow snout. One was wide for the water the other is narrow for the wine. The priests poured the wine and water into each of their bowls. The wine and water mixed together. The wine flowing slowly through the narrow snout and the water flowing quickly through the wider snout. (m.Sukkot 4:9)
Similar imagery appears in the Book of Enoch:
And in that place I saw the fountain of righteousness
Which was inexhaustible:
And around it were many fountains of wisdom:
And all the thirsty drank of them,
And were filled with wisdom,
And their dwellings were with the righteous and holy and elect.
And in the Mishna:
…Let your house be a gathering place for sages…
and drink in their words with gusto.