When Moses communicated to the people through their elders this incomparable promise of the Lord, they promised unanimously (יחדּו) to do all that Jehovah said; and when Moses reported to the Lord what the people had answered, He said to Moses, "I will come to thee in the darkness of the cloud, that the people may listen to My speaking to thee (בּ שׁמע, as in Genesis 27:5, etc.), and also believe thee for ever." As God knew the weakness of the sinful nation, and could not, as the Holy One, come into direct intercourse with it on account of its unholiness, but was about to conclude the covenant with it through the mediation of Moses, it was necessary, in order to accomplish the design of God, that the chosen mediator should receive special credentials; and these were to consists in the fact that Jehovah spoke to Moses in the sight and hearing of the people, that is to say, that He solemnly proclaimed the fundamental law of the covenant in the presence of the whole nation (Exodus 19:16-20:18), and showed by this fact that Moses was the recipient and mediator of the revelation of God, in order that the people might believe him "for ever," as the law was to possess everlasting validity (Matthew 5:18).

Exodus 19:13 Parallel Commentaries

whether

Exodus 21:28,29 If an ox gore a man or a woman, that they die: then the ox shall be surely stoned, and his flesh shall not be eaten...

Leviticus 20:15,16 And if a man lie with a beast, he shall surely be put to death: and you shall slay the beast...

when the trumpet, or cornet

Exodus 19:16,19 And it came to pass on the third day in the morning, that there were thunders and lightning, and a thick cloud on the mount...

1 Corinthians 15:52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible...

1 Thessalonians 4:16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God...