Verse 16. Now at length is come that memorable day, in which Israel heard the voice of the Lord God speaking to them out of the midst of the fire and lived, Deut. iv, 33. Never was there such a sermon preached before or since, as this, which was here preached to the church in the wilderness. For, the preacher was God himself, ver. 17, The Lord descended in fire; and ver. 18. The Lord came down upon mount Sinai. The Shechinah, or glory of the Lord, appeared in the sight of all the people; he shined forth from mount Paran with ten thousand of his saints, attended with a multitude of the holy angels. Hence the law is said to be given by the disposition of angels, Acts vii, 53. He spake from mount Sinai, hung with a thick cloud, ver. 16, covered with smoke, ver. 18, and made to quake greatly. Now it was that the earth trembled at the presence of the Lord, and the mountains skipped like rams, Psalm cxiv, 4, 7, that Sinai itself, though rough and rocky, melted from before the Lord God of Israel, Jude v, 5. The congregation was called together by the sound of a trumpet exceeding loud, ver. 16, and waxing louder and louder, ver. 19. This was done by the ministry of the angels, and made all the people tremble. The introductions to the service were thunders and lightnings, ver. 16. These have natural causes; but the scripture directs us in a particular manner to take notice of the power of God, and his terror in them. Thunder is the voice of God, and lightning the fire of God, proper to engage both the learning senses of seeing and hearing.