The captain of the Lord’s army said to Joshua, “Remove your sandals from your feet, because the place where you are standing is holy (set apart to the Lord).” And Joshua did so. [Ex 3:5]
Then God said, “Do not come near; take your sandals off your feet [out of respect], because the place on which you are standing is holy ground.”
Now Jericho [a fortified city with high walls] was tightly closed because [of the people’s fear] of the sons of Israel; no one went out or came in.
and we [actually] heard this voice made from heaven when we were together with Him on the holy mountain. [Matt 17:6]