Heb 12:19

“700. – Then when he says, and a tempest, he mentions the things terrifying to the hearing on the part of the Law. Now there were three terrifying things to the Law, namely, the severity of the threats, the strictness of the precepts, and the large number of precepts. In regard to the first he says, and a tempest which, strictly speaking, is a disturbance of the sea; but in a wide sense it is a disturbance of the air accompanied by whirlwind and rain. Hence it signifies the strictness of the precepts, whose fulfillment was enjoined on man as though he were waging war against himself. The voice of words signifies the vast number of precepts. These were God's words spoken by an angel: 'Being ordained by angels in the hand of a mediator' (Gal. 3:19). For God spoke there through angels. All these things were so terrifying that those who heard that voice entreated that no further message be spoken to them. Hence, it is stated in Exodus (20:18): 'Being terrified and struck with fear, they stood afar off, saying to Moses: You speak to us and we will hear. Let not the Lord speak to us, lest we die.'”

“trumpet--to rouse attention, and herald God's approach (Exo 19:16). entreated that the word should not be spoken--literally, "that speech should not be added to them"; not that they refused to hear the word of God, but they wished that God should not Himself speak, but employ Moses as His mediating spokesman. "The voice of words" was the Decalogue, spoken by God Himself, a voice issuing forth, without any form being seen: after which "He added no more" (Deu 5:22).”

“And the trumpet, however, as if in the presence of the king; for this will be in the second coming. "and the voice of words." For Moses spoke, and God answered. Indeed, it was necessary for the voice of God to be formed (Ex. 19:19), so that the lawgiving would be worthy of faith, and it would not be thought to be from Moses, through whom God was about to bring the law.”