The Pulpit Commentary - Exodus 19:21
Charge the people lest they break through — i.e; "lest they force a passage through the barrier made by Moses" in accordance with the command given in Exodus 19:12 . And many of them perish . Irreverent gazing on holy things was forbidden by the law ( Numbers 4:20 ), and on one occasion ( 1 Samuel 6:19 ) was actually punished with death. It did not, however, require a law to make it an offence, natural reason being quite sufficient to teach the duty of reverence. read more
The Pulpit Commentary - Exodus 19:20
On the top of the mount . Not, probably, on the highest point of the Sinaitic group, the Jebel Musa, which is out of sight from the plain Er-Rahah, where the Israelites must have been assembled; but on the highest part of the face of Sinai fronting that plain, the Ras Sufsafeh, which would be to the Israelites at the base "the top of the mount." The Lord called Moses up. Perhaps with Aaron, who certainly accompanied him when he next ascended ( Exodus 19:24 ), and who seems to be... read more