Hebrews 12:18

For you are not come to a mountain, [7] &c. That is, to a mountain on earth that can be touched; to wit, to Mount Sinai, where the law was given to Moses, where the mountain seemed all on fire, with dreadful thunder and lightning, whirlwinds, darkness, tempests, sounding of trumpets, voices, &c. which they who heard excused themselves, begging that Moses only, and not God, might speak to them, for they could not without exceeding consternation think of what was then said; that if any man, or even beast, should touch the mountain, he should be stoned to death. (Exodus xix. 15.) Nay Moses himself, trembling, was frightened. This particular is nowhere mentioned in the Scripture, but the apostle might know it by revelation, or by some tradition among the Jews. (Witham)

[BIBLIOGRAPHY]

Ad tractabilem montem, Greek: pselaphomeno orei. palabilem.