According to Cassuto (whom Constable quoted [here][1]), the priests in the nations surrounding Israel were known to have performed their priestly duties either in the nude or clothed with an ephod. Since Israel was to be for YHWH a beacon of light in the midst of the spiritual darkness surrounding her, her worship of the one true God was to be carried out holily, according to God's instructions. 

I must insert here that God is not a prude. Nakedness is not a big deal to Him. However, in the wake of our first parents' disobedience, what was one of the first things God did for them? He *clothed them* with the skins of animals. From Genesis:

>They [viz., Adam and Eve] heard the sound of the Lord God walking in the garden in the cool of the day, and the man and his wife hid themselves from the presence of the Lord God among the trees of the garden. Then the Lord God called to the man, and said to him, “Where are you?” He said, “I heard the sound of You in the garden, and I was afraid because I was naked; so I hid myself.” And He said, ***, my emphasis*** Have you eaten from the tree of which I commanded you not to eat?” (3:8-11 NASB, my emphasis). 

The fear of exposure before a holy God originated in our first parents, not God. For a priest of the LORD to uncover what the first parents covered--in fear and shame because of their disobedience--would fly in the face of the priest's *raison d'etre*; namely, to intercede before God on behalf of himself and other sinners. 

 


  [1]: https://netbible.org/bible/Exodus+20