Moses
Exodus 20:18BSB·traditional attribution

When all the people witnessed the thunder and lightning, the sounding of the ram’s horn, and the mountain enveloped in smoke, they trembled and stood at a distance.

Matthew Henry Presbyterian @wholebiblehenry

I. The extraordinary terror with which the law was given. Never was any thing delivered with such awful pomp; every word was accented, and every sentence paused, with thunder and lightning, much louder and brighter, no doubt, than ordinary. And why was the law given in this dreadful manner, and with all this tremendous ceremony? 1.

Commenting on Exodus 20:18-21

John Gill Reformed Baptist @doctorgill

And Moses said unto the people,.... By representatives and messengers, the heads of the tribes and elders: fear not; be not afraid of God with a slavish fear; be not afraid of the thunders and lightnings, as if they were like one of the plagues of Egypt, which terrified Pharaoh and his people; be not afraid of being consumed by them, they will do you...

Jamieson-Fausset-Brown Reformed @jfbcommentary

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.