The people are sufficiently admonished in that particular, because as thou didst command this same thing before, Exodus 19:12, so I have informed and warned them of it; so that it may seem superfluous for me to go down again to acquaint them herewith. But God, who better knew the dulness and the hardness of their hearts than Moses did, saw it necessary to repeat the same command again and again. Some read the words interrogatively, lo for halo, as it is 2 Samuel 13:26 2 Kings 5:26 Job 2:10 Zechariah 2:15; May not the people (i.e. some of the people, the priests at least, which, as thou hast now said, may come near to the Lord) go up? Is this a universal prohibition? To this answer is given by a distinction in the next verse, that he and Aaron might come up, but no other.
Related Commentaries of Exodus 19:23
Exodus 19:23
23 And Moses said unto the LORD, The people cannot come up to mount Sinai: for thou chargedst us, saying, Set bounds about the mount, and sanctify it.