More details of the question:
YHWH God visited Moses in Mount Sinai but Moses could see only the back side of God. What could be the shape of God in this context?
Exodus 33:18-23 Moses said, “Please show me your glory.” (19) And he said, “I will make all my goodness pass before you and will proclaim before you my name ‘The LORD.’ And I will be gracious to whom I will be gracious, and will show mercy on whom I will show mercy. (20) But,” he said, “you cannot see my face, for man shall not see me and live.” (21) And the LORD said, “Behold, there is a place by me where you shall stand on the rock, (22) and while my glory passes by I will put you in a cleft of the rock, and I will cover you with my hand until I have passed by. (23) Then I will take away my hand, and you shall see my back, but my face shall not be seen.”
Is God a physical person with literal body parts including a face, a hand and a back? Do we die if we see God’s face, but not if we only see his back?
There are other Bible passages where people saw an angel’s face without any harm. Some examples (and there are more):
Genesis 18 – Three angels spoke with Abraham and Sarah. One of them bore the name of God (Gen 18:23).
Joshua 5 – An angel who was “commander of the LORD’s army” appeared to Joshua.
Judges 6:12 – An angel appeared to Gideon.
Judges 13 – An angel appeared to Samson’s parents before he was born.
1 Kings 19 – An angel appeared to Elijah.
Luke 1:11 – An angel appeared to the father of John the Baptist.
Acts 5:19 – An angel rescued Peter from prison.
I can think of three possible ways of understanding why Moses saw God’s back.
(1) God actually has literal body parts. We can see an angel without being killed. But if we see the face (but not the back or hands) of God then we will die. This is not a satisfactory answer for two reasons that I can think of. It does not explain why Abraham saw the LORD, not just any angel. More importantly it does not make sense for the creator of the universe, who made all things including material things, for himself to be made of the materials he created. And does God need such things as literal hands with opposable thumbs?
(2) Since angels differ in rank, then perhaps some angels (or maybe just one angel) is so highly ranked that these rules about dying apply to them (or him), but not to lesser angels. That is possible, but less likely than the next possibility.
(3) On this particular occasion when Moses witnessed God’s glory, God chose to exhibit such a glorious light that it would have caused death if seen directly. It was for Moses’s benefit that he received the vision, but it is not a literal description of God.