And the sound of a trumpet (Exodus 19:16), and the voice of words (Deuteronomy 4:12); which voice they that heard entreated that no word should be spoken to them more: for they could not endure that which was commanded (rather, enjoined), If even a beast touch the mountain, it shall be stoned (Exodus 19:13; "or thrust through with a dart" is an interpolation in the text from the passage in Exodus): and so terrible was the sight, that Moses said, I exceedingly fear and quake (Deuteronomy 9:19, ἔκφοβός εἰμι, to which ἔντρομος is added in the text.
This saying of Moses was really uttered afterwards, when he was descending from the mount, and became aware of the sin of the golden calf. It was called forth by the people's sin, but was due to the alarming character of the preceding phenomena, of τὸ φανταζόμενον, that which was being revealed or manifested.
Mention of it is added here to show that the general fear extended even to Moses, the mediator). This whole account, thus powerfully condensed from Exodus and Deuteronomy, presents a vivid picture of the terrors of the Mosaic revelation.
God was, indeed, revealed to man, but still as unseen and unapproachable, terrible in his wrath against sin, and surrounded by sounds and sights of fear. But now mark the serene and glorious contrast.