"The number six" in the spiritual and figurative sense means incompleteness, incompleteness of spiritual "creation", "creation" in man of the flesh - the true Man, according to the spiritual "Image" and "Likeness" of God.
"The number six" is a symbol of spiritual imperfection, incompleteness, incompleteness, lack of spiritual harmony of man's will with the Will of God.
"The number six" is also the definition of the characteristic of man-materialist, his choice of his own creaturely laws, morals, and actions performed contrary to the Will of God.
The number "six" repeated three times (666) - expresses the threefold confirmation of any imperfection in relation to "number seven", as a symbol of the physical and spiritual perfection of God's Creations.
The number "six hundred and sixty-six" (666) symbolizes a set of cruel, sinful economic, political and religious ideologies and systems of the world, which throughout history have ruthlessly plunged nations into bloody confrontations and wars. The threefold repetition of the number six also symbolizes the manifestation of all god-hating, God-fighting forces of the world by the nations.