Midrash su Levitico 19:30

7) (Vayikra 19:30) ("My Sabbaths you shall keep, and My sanctuary you shall fear; I am the L–rd.") 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.

8) This tells me only of the time when the Temple existed. Whence do I derive the same (i.e., that one must deport himself 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, fearing of the sanctuary is eternal.

9) Which 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 short-cut of it — and, it goes without saying, he must not spit in it.