Compare Deuteronomy 5:22-31. Aaron Exodus 19:24 on this occasion accompanied Moses in drawing near to the thick darkness.

Exodus 20:22 to Exodus 23:33 is a series of laws which we may identify with what was written by Moses in the book called the book of the covenant, and read by him in the audience of the people Exodus 24:7.

The document cannot be regarded as a strictly systematic whole. Portions of it were probably traditional rules handed down from the patriarchs, and retained by the Israelites in Egypt.

And all the people saw the thunderings, etc. - They had witnessed all these awful things before, (see Exodus 19:16), but here they seem to have been repeated; probably at the end of each command, there was a peal of thunder, a blast of the trumpet, and a gleam of lightning, to impress their hearts the more deeply with a due sense of the Divine Majesty, of the holiness of the law which was now delivered, and of the fearful consequences of disobedience. This had the desired effect; the people were impressed with a deep religious fear and a terror of God's judgments; acknowledged themselves perfectly satisfied with the discoveries God had made of himself; and requested that Moses might be constituted the mediator between God and them, as they were not able to bear these tremendous discoveries of the Divine Majesty. "Speak thou with us, and we will hear; but let not God speak with us, lest we die;" Exodus 20:19. This teaches us the absolute necessity of that great Mediator between God and man, Christ Jesus, as no man can come unto the Father but by him.

And all the people saw the thunderings, and the lightnings,.... That is, they heard the one, and saw the other; they heard the dreadful volleys of thunder, and saw the amazing flashes of lightning, which were like lamps and torches, as the word used signifies; by a communication of senses, one sense is put for another, and the sense of sight being the principal, as Ben Melech observes, it is put for the rest, and so in the following. It is an observation of Austin's (o) that to "see" is used of all of the five senses, seeing, hearing, tasting, smelling, and feeling:

and the noise the trumpet, and the mountain smoking: they the sound of the trumpet, which made them tremble and saw the mountain all in a smoke, which made it look very terrible. Though the words may be rendered, as they are by some, "they perceived the thunders", &c. (p); had a sensible perception of them with their eyes ears, which greatly affected them, and made strong impressions upon their minds, and filled them with fear and dread:

and when the people saw it, they removed, and stood afar off; their minds were not only terrified and distressed, and their bodies shook with fear; but they could not stand their ground, but were obliged to retreat, who but just before were curious to draw near, and gaze and see what they could, to prevent which bounds were set; but now these were needless, what they saw and heard were sufficient to keep them at a distance, nay, obliged them to quit their places; they were at the lower part of the mount before, and now they removed a good way from it, even to their camp, and to their tents in it, see Deuteronomy 5:30. The Targum of Jonathan says, they removed twelve miles; and so Jarchi, who observes, that this was according to the length of their camp.

(o) Confess. l. 10. c. 35. (p) "percipiebant", Junius & Tremellius, "intelligebant"; so some in Drusius.

(cf. Deuteronomy 5:19-33). The terrible phenomena, amidst which the Lord displayed His majesty, made the intended impression upon the people who were stationed by the mountain below, so that they desired that God would not speak to them any more, and entreated Moses through their elders to act as mediator between them, promising at the same time that they would hear him (cf. Exodus 19:9, Exodus 19:16-19). ראים, perceiving: ראה to see being frequently used for perceiving, as being the principle sense by which most of the impressions of the outer world are received (e.g., Genesis 42:1; Isaiah 44:16; Jeremiah 33:24). לפּידם, fire-torches, are the vivid flashes of lightning (Exodus 19:16). "They trembled and stood afar off:" not daring to come nearer to the mountain, or to ascend it. "And they said," viz., the heads of the tribes and elders: cf. Deuteronomy 5:20, where the words of the people are more fully given. "Lest we die:" cf. Deuteronomy 5:21-23. Though they had discovered that God speaks with man, and yet man lives; they felt so much that they were בּשׂר, flesh, i.e., powerless, frail, and alienated by sin from the holy God, that they were afraid lest they should be consumed by this great fire, if they listened any longer to the voice of God.

And all the people saw the thunderings, and the lightnings, and the noise of the trumpet, and the mountain smoking: and when the people saw it, they removed, and stood afar off.

20:18 They removed and stood afar off - Before God began to speak, they were thrusting forward to gaze, but now they were effectually cured of their presumption, and taught to keep their distance.

Margin afar off

For contrast between law and grace, cf. Eph 2:13 Lk 1:10 with Heb 10:19-22.

18-21. all the people saw the thunderings and the lightnings-They were eye and ear witnesses of the awful emblems of the Deity's descent. But they perceived not the Deity Himself.

20:18-21 This law, which is so extensive that we cannot measure it, so spiritual that we cannot evade it, and so reasonable that we cannot find fault with it, will be the rule of the future judgment of God, as it is for the present conduct of man. If tried by this rule, we shall find our lives have been passed in transgressions. And with this holy law and an awful judgment before us, who can despise the gospel of Christ? And the knowledge of the law shows our need of repentance. In every believer's heart sin is dethroned and crucified, the law of God is written, and the image of God renewed. The Holy Spirit enables him to hate sin and flee from it, to love and keep this law in sincerity and truth; nor will he cease to repent.