Leviticus 11:45 For I am the Lord that bringeth you up out of the land of Egypt, to be your God: ye shall therefore be holy, for I am holy.

The word holy is an adjective that means pure, clean, free of defilement, and in the case of God, the Holy One of Israel, to never have suffered that condition. Purification, a process required of man, to become holy and therefor able to come before God, is never applied to God.

1 Corinthians 3:17 If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.

Consider this if you would, that God, who is holy, pure and undefiled, should ever be touched by any impure thing, He would cease to be God. His Holiness would consume any amount of sin that even tried to come in His presence.

Deuteronomy 9:3-4 Understand therefore this day, that the Lord thy God is he which goeth over before thee; as a consuming fire he shall destroy them, and he shall bring them down before thy face: so shalt thou drive them out, and destroy them quickly, as the Lord hath said unto thee. Speak not thou in thine heart, after that the Lord thy God hath cast them out from before thee, saying, For my righteousness the Lord hath brought me in to possess this land: but for the wickedness of these nations the Lord doth drive them out from before thee.

Leviticus 22:3 Say unto them, Whosoever he be of all your seed among your generations, that goeth unto the holy things, which the children of Israel hallow unto the Lord, having his uncleanness upon him, that soul shall be cut off from my presence: I am the Lord.

Because of just one act of disobedience Adam and Eve were cut off from the presence of God.