The "door"/"gate" of Jesus and Heaven is obviously a metaphor for the the cross, which became syncretized with the cross of the equinox associated with solar gods like Horus, Apollo and Helios. The
Pyramid Texts, call these two regions the "
Double Doors of the Horizen, and they were the portals through which Re entered and left the Underworld (or in the
Books of the Sky, they were the mouth and vagina of Nut, with Re being reborn at dawn).
The Oddyssey referes to them as the
Gates of the Sun, and Porphyr and Julian (or Iamblicus, can't remember) states that it was through these gates that the soul entered and existed the material realm. (The Jewish custom of opening windows (literal, not figurative) to allow the soul of the newly deceased to leave, is similar in concept). This cross is held by Helios and Apollo as it encircles the celestial globe; and the Lion-headed god of Mithraism stands upon a globe etched with this cross. The zodiac from Denderah shows the equinox occuring in Aries, with Horus depicted right over it, emphazing this as the place where Horus entered the Underworld.
It is also this cross that Plato (or Timaeus if you want to get particular) says was were the demiuge tied the two materials (heavenly and physical) together. Justin Martyr compares not only Jesus's crucifixion with this philosophy, but also Moses placing the brazen serpant upon his staff.
There could also be a subsidiary motive here. Obsereve from
Genesis, 7:11:
In the six hundredth year of Noah's life, in the second month, on the seventeenth day of the month, on that day all the fountains of the great deep burst forth, and the windows of the heavens were opened.
emphasis added
And it is only Johannine material that referes to Jesus as the door.
But one of the soldiers pierced his side with a spear, and at once there came out blood and water.
This synchs up rather well with the Valentinian model of Stauros being the barrier (door, gate, window, and so forth) seperating the Pleroma and the lower realms. This Stauros figure is predicated on the far older Herm and Hermae boundary markers, which were also used to endow men with greater members and increased fertility. It's also curious if the many depictions of Christ with an obvious phallus on his abdomen is a carryover from this idea.
In summary, here are the main points to consider:
*That the door of Jesus was the cross
*That this cross was associated with the cross of the equinox, which was itself refered to as doors, gates, and windows in various other religions
* That the death of Jesus in
John is modeled after the Flood account of
Genesis
* This cross was imagined by some Gnostics to be the barrier between this world and the realm of the Pleroma
* And that this cross has connections to the Herm boundary markers, which were used to increase fertility among men
* When taken together, this could mean that the new baptism issued (literally) from Jesus upon his death, was advertently and implicitly, a sexual baptism. (You can imagine what he was actually issuing from himself).