The Mohammedans, when about to perform their devotions, always leave their slippers at the door of the mosque. The Druids practised the same custom whenever they celebrated their sacred rites; and the ancient Peruvians are said always to have left their shoes at the porch when they entered the magnificent temple consecrated to the worship of the sun. Adam Clarke thinks that the custom of worshipping the Deity barefooted was so general among all nations of antiquity, that he assigns it as one of his thirteen proofs that the whole human race have been derived from one family.[92] A theory might be advanced as follows: The shoes, or sandals, were worn on ordinary occasions as a protection from the defilement of the ground. To continue to wear them, then, in a consecrated place, would be a tacit insinuation that the ground there was equally polluted and capable of producing defilement. But, as the very character of a holy and consecrated spot precludes the idea of any sort of defilement or impurity, the acknowledgment that such was the case was conveyed, symbolically, by divesting the feet of all that protection from pollution and uncleanness which would be necessary in unconsecrated places. So, in modern times, we uncover the head to express the sentiment of esteem and respect. Now, in former days, when there was more violence to be apprehended than now, the casque, or helmet, afforded an ample protection from any sudden blow of an unexpected adversary. But we can fear no violence from one whom we esteem and respect; and, therefore, to deprive the head of its accustomed protection, is to give an evidence of our unlimited confidence in the person to whom the gesture is made. The rite of discalceation is, therefore, a symbol of reverence. It signifies, in the language of symbolism, that the spot which is about to be approached in this humble and reverential manner is consecrated to some holy purpose. Now, as to all that has been said, the intelligent mason will at once see its application to the third degree. Of all the degrees of Masonry, this is by far the most important and sublime. The solemn lessons which it teaches, the sacred scene which it represents, and the impressive ceremonies with which it is conducted, are all calculated to inspire the mind with feelings of awe and reverence. Into the holy of holies of the temple, when the ark of the covenant had been deposited in its appropriate place, and the Shekinah was hovering over it, the high priest alone, and on one day only in the whole year, was permitted, after the most careful purification, to enter with bare feet, and to pronounce, with fearful veneration, the tetragrammaton or omnific word.