This is about worship proximity. There were a series of imaginary circles around Mount Sinai. God was the only one on the inside of the center circle; Father, Son and Holy Ghost... alone and sufficient in the middle of the ring. Outside of that, all of humanity stood afar off, not close enough to see whatever manifestation of God's presence was there. But, not everybody stood the same distance from their God. Moses was closest. Joshua was inside of a little larger ring. Aaron, Nadab & Abihu and 70 national elders were a little ways further off. Then came the nation, cowering in respectful fear ... some tribes no doubt closer than others. And, last of all, the rest of the world at that time, all Gentiles, remained outside of the largest circle... oblivious to the Divine revelation which was in progress (Ephesians 2:17 & 14-22).
There is one really interesting matter that is brought up in this text: seeing God. What did the 74 people actually see? Whatever they saw, it had no form (Deuteronomy 4:15 & 14-19). Yet, they definitely saw something (Exodus 24:10-11). I don’t think I’m qualified to delve into the comparison of this account with claims like the ones in John 1:18, I Timothy 6:16 & I John 4:12. But, we have no choice but to believe both, yet how they are to be reconciled is a mystery.
What I do notice though is the consistency in this encounter with other similar accounts of a couple of other Bible authors. In this passage it is recorder that "there was under His feet as it were a paved work of a sapphire stone, and as it were the body of heaven in His clearness." Ezekiel and John both had comparable impressions when viewing the place where God was (Ezekiel 1:26 & 28:14 and Revelation 4:6 & 15:2). Whatever it was like, it was obviously something very different than anything we have ever seen. And, why not? One would expect God's throne room to be rather exquisite and unique. Of course, it looked quite different from a distance (Exodus 24:17).
One final comment here: for the first time I noticed that the people actually received the laws of God prior to the issuing of the tablets of stone. The Ten Commandments were known before they were miraculously written in stone. That is very important to know.