Exodus 3:5
And he said, Draw not near here: put off your shoes from off your feet, for the place where on you stand is holy ground.
Nave's Topical Index—AKJV

Exodus 19:12,13
And you shall set bounds to the people round about, saying, Take heed to yourselves, that you go not up into the mount, or touch the border of it: whoever touches the mount shall be surely put to death:
Nave's Topical Index—AKJV

Hebrews 12:18-24
For you are not come to the mount that might be touched, and that burned with fire, nor to blackness, and darkness, and tempest,
Nave's Topical Index—AKJV