The prospect of any man, at any time, ever seeing God in His glory, is virtually non-existent. But for those who were privileged to live back then, they had a flesh and blood witness—God incarnate. And for those of us who live now, we have His Word that is based upon eyewitnesses of His glory, of His grace. This is why Jesus said what He did, in John 14, when He was asked to show us the Father. In John 14:6, Jesus said:
Grace incarnate arrived before men. The great gift, you see, that gives us delight from which we receive salvation; from which, as we just saw, we receive the calling. No one can go to the Father except through Him.
So God uses this introduction to the book of John to make clear a very important fact and concept. The fact and concept are one and the same, and that is that God is not a being detached and separated from His creation. He is not merely exalted and worshipped, but God is involved. He takes part in the process. He loves, He yearns, He suffers, He gives, He corrects, and He saves. He enters right into the storms and conflicts of life on earth, and in the life of Jesus, He was subject to all of its conditions and He rose above it. He conquered sin and Satan. It says in Hebrews that "He was tempted in all things like as we are, yet without sin."
And so in Christ, then, in a life lived, God ceases to be an abstraction and becomes a reality. The incarnation, then, was the fullest manifestation of grace and truth because it was the greatest expression of God's concern and compassion for people, and the clearest way of conveying for our understanding. No one can ever forget the power of an example.