The reality is that the document is here. I can't see any rational reason to doubt its authenticity so I am forced to adapt my theory to its testimony.
What I have been thinking about for a seeming eternity now ever since I published that post is how strange that formulation must seem to regular readers of my blog. I mean I spent months arguing that the Markan baptism was identified as a 'redemption' baptism because it developed from the Jewish and Samaritan ritual concept of גאלה associated with the Crossing of the Sea in Exodus and now I am arguing that it has something to do with a 'baptism on behalf of the dead.'
Am I giving up on the idea of redemption?
Well clearly it would be impossible for me to abandon my original theory as the sources tell us that it was BOTH a 'redemption' ritual AND a baptism in which the initiates were understood to be dead. But how could this be? In what sense could the followers of Mark have applied 'death' to the 'crossing of the Sea' when the Israelites all made it through the waters safely.
The first thought that jumped into my head was Tertullian's remark that the Marcionites understood that Christianity was exclusively directed at proselytes to Judaism (Tert ) As such this means that these are people who are not yet 'fully Jewish' but have a deep understanding of basic religious concepts, likely can function in Hebrew or Aramaic but just happen to have ancestors who aren't 'sons of Abraham.'
If we imagine further that the apostle engaged in a call to the Egyptians (self-evident because the Marcionites had an Epistle to the Alexandrians in their canon that I have already identified with our First Letter to the Corinthians) in some sense the ancestors of these proselytes would have been on the other side of history of the Exodus. Rather than walking on the land which was cleared by the parting of the sea, their fathers would have drowned in the waters as described in the Song of the Sea and the Exodus narrative.
With me so far?
Now let's go to the various statements that emerge from the writings against the Marcionites about the Marcionite interest in the Egyptians. The first is the statement that gets recycled from Irenaeus in Tertullian countless times that God was angry at the Jews for stealing the Egyptian silver and gold. Unfortunately I don't have time to examine this in detail here but it should be made clear that this line of argument actually is witnessed in early rabbinic texts (cf. Sanhedrin 102a, Berakoth 32a etc).
What I would like to remind the reader about is how many times we are told that the Marcionites took an interest in the drowned Egyptians. We begin with Charles Evan Hill's well researched argument that shows that Irenaeus claimed that Polycarp (identified as 'the presbyter' throughout Against All Heresies) developed a systematic response to a Marcionite theology developed IN FAVOR of the losing side in the Exodus. Hill writes:
The presbyter's teaching shows that the story of the exodus played a large part in Marcion's argument in the Antitheses. From it he was able to extract three objections: against the God who would harden the hearts of Pharaoh and his people (4.29.1), against the people who the Egyptians and the God who would use these stolen goods for the construction of his tabernacle (4.30.1) and against the God who would send plagues upon the Egyptians and then drown them in the sea to effect his people's salvation (4.28.3). [Hill, the Lost Teachings of Polycarp p. 90]
I don't think I need to cite the section from Irenaeus just now. I have always thought Hill's book was nothing short of brilliant. What is more important is that we see that bits and pieces of this Marcionite 'interest' in the drowned Egyptians might well explain the origins of redemption baptism.
Take Tertullian's rejection of the Marcionite interpretation of the words "what manner of man is this? for He commandeth even the winds and water!" (cf. Luke 8:25). He says:
Examine well the Exodus, Marcion; look at the rod of Moses, as it waves His command to the Red Sea, ampler than all the lakes of Judaea. How the sea yawns from its very depths, then fixes itself in two solidified masses, and so, out of the interval between them,736 makes a way for the people to pass dry-shod across; again does the same rod vibrate, the sea returns in its strength, and in the concourse of its waters the chivalry of Egypt is engulphed! [AH iv.20]
One can read the passage in light of Hill's work and argue that Tertullian was also CORRECTING the Marcionite interest in the losing side. In other words, he is saying that Christianity should be rooted in the Israelites crossing the sea rather than the wicked men who drowned in the waters. There are many other passages to this effect in Tertullian (cf AM ii.16) but the strongest statement actually comes from one of our earliest sources - the Five Books of Irenaeus Against All Heresies - where it is said that according to the Marcionites
that Cain, and those like him, and the Sodomites, and the Egyptians, and others like them, and, in fine, all the nations who walked in all sorts of abomination, were saved by the Lord, on His descending into Hades, and on their running unto Him, and that they welcomed Him into their kingdom.[AH i.25.3]
As such I am quite confident that something like what I am suggesting must have been the original context of Markan baptism ROOTED AS IT WAS IN EGYPTIAN SOIL.
It was directed at proselytes, it was a baptism on behalf of the dead and it was conceived as an ἀπολύτρωσις after the manner of the washing of the sea. The way that these ideas come together - I put forward - is that the Marcionites conceived that this ritual washing was established from Jewish proselytes -likely initially in Egypt the existence of whom Philo repeatedly references in his writings.
It is worth noting that MacDonald sees Marqe take an interest in some of the Egyptians that were overcome by water converted to the true religion.
