Jung's Alchemical studies.
"the idea of the divine water was familiar to every alchemist.
When Jesus said: “Except a man be born of water and of the spirit"
an alchemist of that time would have understood what he meant.
Jesus marvelled at the ignorance of Nicodemus and asked him: “Art thou a master in Israel, and knowest not these things?”
a teacher would know the secret of water and spirit,
that is, of death and rebirth..
We speak that we do know, and testify that we have seen.”
"when, in the next verse, Jesus speaks of the serpent lifted up in the wilderness and equates it with his own self- sacrifice,
a “Master” would be bound to think of the uroboros, which slays itself and brings itself to life again.
This is followed by the motif of “everlasting life” and the panacea (belief in Christ).
Indeed, the whole purpose of the opus was to produce the incorruptible body,
“the thing that dieth not,” the invisible, spiritual stone, or lapis aethereus."
"Jesus identifies him self with the healing snake of Moses;
for the Monogenes is synonymous with the Nous, and this with the serpent- saviour or Agathodaimon.
The serpent is also a synonym for the divine water.
The dialogue may be compared with Jesus’words to the woman of Samaria in John 4 : 14:
“. . . a well of water springing up into everlasting life.”
Significantly enough, the conversation by the well forms the context for the teaching that “God is Spirit” (John 4 : 24)."