Moses
Exodus 19:12ESV·traditional attribution

And you shall set limits for the people all around, saying, ‘Take care not to go up into the mountain or touch the edge of it. Whoever touches the mountain shall be put to death.

John Calvin Reformed @genevareformer

12. And thou shalt set bounds. By this symbol the Israelites were admonished to restrain their natural inquisitiveness, that they may be sober in their desires after knowledge, because God, by the teaching of His Law, only enlightens those who are as “little children.” We know how great is men’s natural curiosity, how forwardly they seek to penetrate the secrets of God, how daringly they...

Matthew Henry Presbyterian @wholebiblehenry

Here, I. God intimates to Moses his purpose of coming down upon mount Sinai, in some visible appearance of his glory, in a thick cloud (Exo 19:9); for he said that he would dwell in the thick darkness (Ch2 6:1), and make this his pavilion (Psa 18:11), holding back the face of his throne when he set it upon mount Sinai, and spreading a cloud upon it, Job 26:9.

Commenting on Exodus 19:9-15

John Gill Reformed Baptist @doctorgill

And thou shall set bounds to the people round about,.... That is, round about the mountain, by drawing a line, throwing up a foss or ditch, or else by laying up heaps of stones or sand, which might be come at easily, or bushes and branches of trees, which grew thick on the mount, from whence it had its name; but be it what will...