El Shaddai

"It is a common custom to write [God's name,] Shaddai, on the outside of a mezuzah opposite the empty space left between the two passages. There is no difficulty in this, since [the addition is made] outside.Those, however, who write the names of angels, other sacred names, verses, or forms, on the inside [of a mezuzah] are among those who do not have a portion in the world to come. Not only do these fools nullify the mitzvah, but furthermore, they make from a great mitzvah [which reflects] the unity of the name of the Holy One, blessed be He, the love of Him, and the service of Him, a talisman for their own benefit. They, in their foolish conception, think that this will help them regarding the vanities of the world."

"It is highly likely that Abraham's God was El, the High God of Canaan. The deity introduces himself to Abraham as El Shaddai (El of the Mountain), which was one of El's traditional titles. Elsewhere he is called El Elyon (The Most High God) or El of Bethel. The name of the Canaanite High God is preserved in such Hebrew names as Isra-El or Ishma-El. They experienced him in ways that would not have been unfamiliar to the pagans of the Middle East. We shall see that centuries later Israelites found the mana or "holiness" of Yahweh a terrifying experience. On Mount Sinai, for example, he would appear to Moses in the midst of an awe-inspiring volcanic eruption, and the Israelites had to keep their distance. In comparison, Abraham's god El is a very mild deity. He appears to Abraham as a friend and sometimes even assumes human form. This type of divine apparition, known as an epiphany, was quite common in the pagan world of antiquity."