Exodus 33:20 But He said, “You cannot see My face; for no man shall see Me, and live.”
John 1:18 confirms that no one but Jesus has seen God, so how does this square with the Bible's own description of Moses, Jacob and Sampson's parents encountering God? In verse 11 of the same chapter of Exodus, Moses speaks to God "face to face." This is a figure of speech for intimate conversation, as at the end of the chapter Moses is intentionally shielded in the rocks of the mountain side from seeing God, experiencing only the trail of His glory.
Jacob sees God appearing as a man in Genesis 32:30 and Samson's parents seem to encounter God appearing as an angel in Judges 13:22. Jesus tells Philip in John 14:9 that, "Anyone who has seen Me has seen the Father." We can conclude that people have seen God but not plainly seen God in all His Glory.