Exodus 3:6 says that from the bush Moses heard, "I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob." Now, Moses' reaction was natural enough. He did what anyone would do. He "hid his face; for he was afraid to look upon God." When an unholy and unrighteous weakling is brought into the presence of the holy and righteous Almighty, shame and fear are appropriate. But, the situation begs an interrogation. This "looking upon God" thing... what's that all about?
1Timothy 1:17 says plainly that our God is invisible. What is the point in or
possibility of the seeing of anything that is invisible? It's like wanting to smell the rainbow or listen to the sun shine. It's like desiring to taste thunder or to touch an aroma. The sensory interests don't seem to fit with the reasonable possibilities. Yet, we read in Hebrews 11:27 that Moses had indeed "seen Him who is invisible" back when he was still in Egypt. Not only that, Exodus 33:18-20 says that he later asked to see "God's glory" and was told that he wouldn't survive it.
In the New Testament it is written that no man has ever seen God (John 1:18, I Timothy 6:16 & I John 4:12). Yet, the prophets Micaiah, Amos and Isaiah all claimed to have seen Him (Isaiah 6:1, Amos 9:1 & II Chronicles 18:18).
Essentially the answer can be summed up in one word; faith (Hebrews 11:1). We must believe what the Scriptures says. Look at John 1:18 again: “No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, He hath declared Him.”