Holy Ground, Part II

Ex 3.5, "Then He said, 'Do not come near; take your sandals off your feet, for the place on which you are standing is holy ground.'"
I see three possible explanations:

Possibility 1. This is primarily a negative command, remove your shoes. Moses' sandals are incompatible with the holy ground, somehow. Perhaps there's something symbolically offensive about footwear when its juxtaposed with holy ground.

Possibility 2. This is primarily a positive command, make yourself barefoot. Something about holy ground requires barefeet. So, Moses' sandal is only important insofar as it happens to be the object that forms a barrier between his foot and the ground.

Possibility 3. Both of the above.