Hebrews 12:19

Wonderful indeed were the things in the Temple, the Holy of Holies; and again awful were those things also that were done at Mount Sinai, "the fire, the darkness, the blackness, the tempest." For, it says, "God appeared in Sinai," and long ago were these things celebrated. The New Covenant, however, was not given with any of these things, but has been given in simple discourse by God. See then how he makes the comparison in these points also. And with good reason has he put them afterwards. For when he had persuaded them by innumerable arguments, when he had also shown the difference between each covenant, then afterwards, the one having been already condemned, he easily enters on these points also. These things, he means, are terrible; and so terrible that they could not even bear to hear them, that not even "a beast" dared to go up. For it is said, "Let not God speak, but let Moses speak unto us. And so fearful was that which was commanded, Though even a beast touch the mountain, it shall be stoned; Moses said, I exceedingly fear and quake." What wonder as respects the people? He himself who entered into "the darkness where God was," saith, "I exceedingly fear and quake." Fearful were those things, but these are far more admirable and glorious. For here there is not "darkness," nor "blackness," nor "tempest." It seems to me that by these words he hints at the obscurity of the Old Testament, and the overshadowed and veiled character of the Law. And besides the Giver of the Law appears in fire terrible, and apt to punish those who transgress. But what are "the sounds of the trumpet"? Probably it is as though some King were coming. This at all events will also be at the second coming. "At the last trump" all must be raised. But it is the trumpet of His voice which effects this. […]

While he brought out the fearsome things, he did not reveal the fruit springing from them. He did not say he "appeared," because what they saw was not the God of all in person but some impression of the divine coming.

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 …

He shows that if they do not endure and at the same time do not believe in the promises, they are far more guilty than those under the Old Testament. And see how he makes the comparison. Having shown the superiority of the New Testament …

The sound of a trumpet - Formed, without doubt, by the ministry of angels, and preparatory to the words, that is, the Ten Commandments, which were uttered with a loud voice, Deut. v, 22.