Sifra on Respect for the Temple Site

MY SABBATHS YOU SHALL KEEP, AND MY SANCTUARY YOU SHALL FEAR; I AM THE LORD (Leviticus 19:30). I might think that the building of the Temple countermanded the [keeping of the] Sabbath; it is therefore written: My Sabbaths you shall keep, and My sanctuary you shall fear. I might think that one should fear the sanctuary; it is therefore written: My Sabbaths you shall keep, and My sanctuary you shall fear. Just as with the Sabbath it is not the Sabbath that you fear but Him who commanded that the Sabbath be kept, so with the sanctuary it is not the sanctuary you fear but Him who commanded concerning it.

This tells me only of the time when the Temple existed. Whence do I derive the same [i.e., that one must comport oneself with fear at the Temple site] even when the Temple does not exist? From My Sabbaths you shall keep, and My sanctuary you shall fear. Just as the keeping of the Sabbath is eternal, so the fearing of the sanctuary is eternal.

What is FEAR? One should not enter the Temple Mount with his staff and with his traveling bag, with his shoes, with his money belt, and with the dust on his feet, and he must not make a shortcut of it—and, it goes without saying, he must not spit in it.