“And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, that whoever believes in him may have eternal life.”
I think that John 3:14-15 helps greatly to explain the presence of the two crucified thieves with Jesus:
Mark 15:24, 27, 32:
And they crucified him … They crucified two rebels with him, one on his right and one on his left. ... Those crucified with him also heaped insults on him.
Exodus 7,8–13 :
8 Now the Lord spoke to Moses and Aaron, saying,
9 “When Pharaoh speaks to you, saying, ‘Work a miracle,’ then you shall say to Aaron, ‘Take your staff and throw it down before Pharaoh, that it may become a serpent.’ ”
10 So Moses and Aaron came to Pharaoh, and thus they did just as the Lord had commanded; and Aaron threw his staff down before Pharaoh and his servants, and it became a serpent.
11 Then Pharaoh also called for the wise men and the sorcerers, and they also, the magicians of Egypt, did the same with their secret arts.
12 For each one threw down his staff and they turned into serpents. But Aaron’s staff swallowed up their staffs.
13 Yet Pharaoh’s heart was hardened, and he did not listen to them, as the Lord had said.]
9 “When Pharaoh speaks to you, saying, ‘Work a miracle,’ then you shall say to Aaron, ‘Take your staff and throw it down before Pharaoh, that it may become a serpent.’ ”
10 So Moses and Aaron came to Pharaoh, and thus they did just as the Lord had commanded; and Aaron threw his staff down before Pharaoh and his servants, and it became a serpent.
11 Then Pharaoh also called for the wise men and the sorcerers, and they also, the magicians of Egypt, did the same with their secret arts.
12 For each one threw down his staff and they turned into serpents. But Aaron’s staff swallowed up their staffs.
13 Yet Pharaoh’s heart was hardened, and he did not listen to them, as the Lord had said.]
I think that there is a particular pattern in how Mark builds the his story:
1) he takes a previous myth (myth, not story or legend)
2) and he historicizes it by inventing human figures for the circumstance.
Another example:
Isn’t this the carpenter? Isn’t this Mary’s son and the brother of James, Joseph, Judas and Simon? Aren’t his sisters here with us?” And they took offense at him.
(Mark 6:3)
The «carpenter» is the demiurge. «Mary» is Sophia, the mother of the demiurge. The people of Nazareth are scandalized to recognize Jesus as the figure of the creator still only partially rehabilitated in the eyes of the Judaizers. In this way, «Mark» confirms us in the total rehabilitation of the creator as the supreme god. Something as:
«Ok, we know that the demiurge is going to be rehabilitated gradually, but don't fear, in the my story the process of rehabilitation of the demiurge, in the form of a human messiah called Jesus, is complete».
Another example still:
And he was there in the wilderness forty days, tempted of Satan; and was with the wild beasts; and the angels ministered unto him.
(Mark 1:13)
The scene is anti-edenic. The «wilderness» is the anti-Eden, the «wild beasts» are the animals found in this anti-Eden, and Jesus is put there as a new Adam, having even the «angels» in the his service.
The Garden of Eden is now a Wilderness because of the Original Sin.
But then who is «Satan»? He is the «Serpent» who tempted Adam and Eve. In this way the Judaizer «Mark» is claiming that the creator is the supreme god, and not the Serpent adored by the gnostics as a positive figure. But here is again the same pattern in action: the figures of the gnostic myth are used by Mark to invent a new story in order to debunk that previous myth.