And the people stood afar off repeats the words in verse 18. (See the comment there.) While Moses drew near is literally “and Moses approached.” To the thick darkness is literally “unto the cloud,” referring to a very dense cloud. So Good News Translation and others have “the dark cloud” (similarly New Jerusalem Bible, Revised English Bible, and Translator’s Old Testament). But the word also means darkness or gloom, and New Revised Standard Version retains this meaning (similarly New International Version, American Standard Version, and Moffatt). Where God was is literally “where there [was] the ʾelohim.” This means that God was concealing himself from the people by means of “the dark cloud.” It is possible to put this final sentence first and say “But when Moses went near the dark cloud where God was, the people stayed at a distance.”

Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .