Moses wanted to see the face of God.
This may have been a presumptuous request but it was very human.
People still want God to show Himself.
Preincarnat Jesus speaks to Moses about His goodness and may have even given Him His name. He tells Him of His Grace that comes out of His goodness and His love. How that He will be merciful out of His own goodness.
God is a Spirit. He is the Holy Spirit. → physical beings cannot see spiritual things with their eyes → God created the vast universe so He is bigger than what He created.
Seeing and living implies that a living physical human cannot see the Holy Spirit.
Jesus confirmed this to Nocodemus saying that the Holy Spirit is not visible. You only see the evidence of Him by that which He effects.
The one speaking to Moses is preincarnate Jesus whom neither Moses nor anyone living at that time could see because it was not yet time for the Holy Spirit to reveal Himself to mankind In Christ Jesus.
This statement is a specific instance of the general: If you believe you will see the glory of the Lord.
We cannot see the Holy Spirit but we can see His glory in the face of Jesus Christ our Saviour and Lord.
What is Holy Spirit glory? It is the intensity, consistency, persistence and pervasiveness of His love.
It is in the knowledge of His glory, His love, that our lives are lit up.
Our Lord Jesus Christ is the proof of Holy Spirit love manifesting His glory.
Faith in the love of the Lord is foundational to receiving the things of of the Lord.
Jesus is The Glory Of God.
Here we see our Lord Jesus, who is the Lamb slain before the foundation of the world, being the light of our lives.