Hebrews 12:20

For they could not bear what was commanded: “If even an animal touches the mountain, it must be stoned.”

Note Exodus 19:12–13

(For they could not endure that which was commanded, And if so much as a beast touch the mountain, it shall be stoned, or thrust through with a dart:

for they could not stand that which was commanded, “If even an animal touches the mountain, it shall be stoned”.

Note TR adds “or shot with an arrow”

for they could not endure that which was enjoined, If even a beast touch the mountain, it shall be stoned;