Exodus 33:20

And he said, Thou canst not see my face: for there shall no man see me, and live.

Thou canst not see my face - i:e., the real unveiled effulgence of the divine glory.

For there shall no man see me, and live - a traditional belief obtained through all pagan antiquity, that the appearance of God, or a divine being, to any one, would be followed by the speedy death of that person. But this belief, which among the pagan was the mere effect of superstitious fear, became a settled opinion, common sentiment founded on a deep feeling of unworthiness to appear before God, among the pious in the ancient Church.

Numerous instances of this persuasion occur in the Old Testament history (Genesis 16:13; Genesis 32:30; Judges 6:22; 13:26; Isaiah 6:5); and in this passage the Divine Being Himself confirms the fact that a full disclosure of the divine glory is incompatible with the present condition of humanity, and can be exhibited only to the organs of the spiritual body (1 Corinthians 15:44: cf. 2 Corinthians 12:2).