When the serpent mounted eve, he injected filth into her. Israel who
stood at Mount Sinai, their filth ceased; the other nations who did not
stand at Mount Sinai, their filth has not ceased....
Kabbala: Zohar 1:37a
R. Hiyya said: "The sons of God were the sons of Cain. For when Samael
mounted Eve, he injected filth into her, and she conceived and bare
Cain. And his aspect was unlike that of the other humans and all those
who came from his side were called sons of God."
Midrash: Pirqe R. Eliezer. Ch. 13
Samael was the greatest prince in heaven. The celestial animals and the
Seraphim had six wings each, but Samael had twelve. He took his cohorts
and went down, and saw all the creatures whom the Holy One, blessed be
He, had created, and found among them none as astute and malicious as
the serpent. And the serpent's appearance was like that of a camel.
And Samael mounted him and rode him. And the Tora cried and shrieked and
said: "Samael, the world has just been created, is this the time to
rebel against God?"
The serpent went and said to the woman: "Is it
true that you are commanded not to eat the fruit of this tree?....