וישׂם יהוה לקין אות לבלתי הכות־אתו כל־מצאו
"And the LORD set a sign for Cain, lest any finding him should smite him." says the verse but what was this mark?
The word in Gen. 4:15 is 'ot' which could mean a sign, an omen, a warning, or a remembrance or taking a scribal stance on it - a letter - heyI can't help it I think about letters a lot. The text describes how the mark was to function as a sign or warning, not what form the mark took.
The Zohar says that the mark of Cain was the letter vav! Was an echo here picked up by the Christians with the vav, vav, vav (666) Number of the Beast famous in the Omen films? Vav is actually a letter denoting completeness and means a hook. Puts me in mind of that scary horror film with the bloke who had lots of hooks in his face. However the Zohar explains that "God inscribed the Hebrew Letter Vav onto the forehead of Cain. The letter Vav connects to the 'Sfirot of Yesod, which signifies the Covenant between God and the Israelites. When Cain sincerely repented for the murder of his brother Abel, the letter Vav protected him from the murderous hands of people which were aroused against him by the spiritual law of cause and effect. Provided we fully repent, meditating upon the letter Vav offers us protection from any decrees of judgment." So Kayin benefitted from a complete (vav) repentance meriting protection,
Rashi says "He inscribed a letter from His Divine Name on his forehead" and that fits with the vav theory too.
In that famous Rabbinical work :) Thoroughly Modern Moses (available through Kulmus Publishing http://www.lulu.com/conten
the author writes of the mark of Cain, 'for in large red English letters, rather similar to those you find stenciled onto a packing crate at a port was the single word ... REJECT'.