Gary Pollard
The practice of immersing someone in water for ritual purposes may go all the way to 3,150 BC at the very beginning of Dynastic Egypt, perhaps 2,000 years before Moses was born. It was for sure a common practice in the Old Kingdom, as we find it mentioned in the Pyramid Texts (which date to about 2,350 BC, or close to 1,000 years before Moses, though parts of it seem to be much older).
The ancient Egyptians believed that the sun “died” every evening, had to swim through the depths of the cosmic ocean, and was reborn every morning at sunrise. There’s ample evidence from the earliest of their writings that this was not originally believed in a literal sense, but was used as a simplified means to communicate information about the movement of celestial bodies. The meaning devolved later into a worship of a sun-god, and every other planet’s representative “deity”.
Either way, there was profound symbolism in the “death” of the sun every evening as it dipped below the horizon of the sea, and its resurrection in the morning as it appeared to come up from the watery horizon to new life. The most important through-line in the practice was ritual death and rebirth. The initiate was washed by water, just as the sun appeared to be every evening. They were no longer the same person that went into the water, just as the sun was renewed every morning. It was death to the old self and rebirth.
Plutarch wrote about baptism in his book On Isis and Osiris (which was published around the same time as John’s writings). In the Roman Era in Egypt, they associated baptism with purification, rebirth (as Osiris rising from the Nile), and initiation into divine mysteries. Water was considered to be the primordial source of all things, and baptism was how one was purified. Plutarch did not apply any of this to Christianity or Christian practices, as far as I know. He was mostly interested in talking about the cycles of the sun as they were represented in Egyptian myths about Osiris.
The important thing is that ancient cultures universally associated baptism with rebirth, and saw a physical analog for this in the rising and setting sun. Many other ancient cultures practiced this in some form, though not all used water — some used blood. The Jewish people used water for ritual cleansing, and John used it to let everyone know that the old system was about to die and be reborn in a superior “body” through Christ.
So seeing baptism as merely an “outward sign of an inward faith” does not appear to have any historical or cultural precedent. For thousands of years before Christianity, it was understood to be a rebirth ritual. You had to have water (or blood) before you could experience new life.
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