Romans 1:20
For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.
^To understand the invisible characteristics of the Almighty, we study what's been made by Him as foreshadowing examples.
Before a person is born into this world they pass through water (the amniotic sac) breaking. Similarly, before a priest was allowed into the personal sanctum of the Almighty (i.e. the inner court) he was required to wash at the bronze laver...then later on when the temple was built this laver was enlarged into the bronze sea to fit many more priests. This bath stood between the altar of sacrifice and the inner court of the temple or holy place.
Matthew 3:13-17
Then cometh Jesus from Galilee to Jordan unto John, to be baptized of him.
14 But John forbad him, saying, I have need to be baptized of thee, and comest thou to me?
15 And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfil all righteousness. Then he suffered him.
16 And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him: And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
The Messiah was born of the water and the Spirit and then was proclaimed "Son".
"That which is born of flesh is flesh"...it must follow the same process no matter the flesh.
"That which is born of spirit is spirit"...it must follow the same process no matter the spirit.