Moses now must re-establish a relationship with God that he feels had been broken. We can understand God’s anger with the Israelites but why with Moses? Yet Moses clearly needs personal reassurance as well as for the people in general.
So he asked God to “show me your glory.” God replied, “no human can actually see God.” But he put Moses in a cleft in the rock, in the same way that we say today “you are in between a rock and a hard place.” When we are under pressure, suffering a crisis, that’s when we want to “see God.” And God covers Moses while he “passes by” and then allows Moses to see an after image. He could not claim to have seen God but to have experienced the impact of God.
Now elsewhere the Torah talks about exchanges between God and Moses. Commands to do and commands to receive and transmit. He is described as speaking to God “Face to Face” and “Mouth to Mouth.” So what more did he want? Well of course all such terms are anthropomorphisms. God has neither a mouth nor a face. They are ways of describing communication of some powerful sort even if the actual mechanisms cannot be put into human language.
But Moses wanted more. He wanted physical certainty. And that is something that is impossible under any conditions because the human mind is such a fluid and flexible organ that we can rarely be absolutely certain of anything, certainly not of something abstract and non-physical. Even proving that we ourselves exist is a challenge to philosophers. Proof might work in science and maths but not with emotions or experiences where we are often deluded. So Moses wanted as much as it was possible to get. He got the shadow, the after image.
And that’s true for us. We cannot see God because God is not physical and we are physical beings. We can only experience electricity if we make the transistors or the connections that convert energy into light and power. All we do experience is the impact of spirituality, goodness and morality. And that was what God wanted, not focus on what He looked like but on how we can make the world better by following His direction. God does not represent an image of what is, but rather an idea and inspiration of what might be if we try to achieve it.