Hebrews 12:21

The sight was so terrifying that even Moses said, “I am trembling with fear.”

Note Deuteronomy 9:19

BSB · Berean Standard Bible
And so terrible was the sight, that Moses said, I exceedingly fear and quake:)
KJV · King James Version
So fearful was the appearance that Moses said, “I am terrified and trembling.”
WEB · World English Bible
and so fearful was the appearance, that Moses said, I exceedingly fear and quake:
ASV · American Standard Version

Related passages

From the Treasury of Scripture Knowledge, grouped by the word they explain.

Moses
Exodus 19:16, 19; Psalm 119:120; Isaiah 6:3–5; Daniel 10:8, 17; Revelation 1:17