The four letters, meaning the four which compose the name of Deity. The ancient Jews never pronounced the word Jehovah composed of the four sacred letters JHVH. The word means “I am,” or “I exist” (Exod. iii. 14); but Rabbi Bechai says the letters include the three times- past, present, and future. Pythagoras called Deity a Tetrad or Tetractys, meaning the “four sacred letters.”
East Indian, ZEUL and ESAI.
Egyptian, ZEUT, AUMN, AMON.
Hebrew, JHVH, ADON.
Persian, SORU, SYRA.
Sredish, OODD, GOTH.
Such was the sacred Tetragrammaton. Things worthy silence must not be revealed.
[We have the Egyptian , like the Greek.]
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894