The lamb has always been considered as an appropriate emblem of innocence, and hence we are taught, in the ritual of the first degree that "by the lambskin," the Mason is reminded of "that purity of life and rectitude of conduct which is so essentially necessary to his gaining admission into the Celestial Lodge above, where the Supreme Architect of the Universe forever presides." The apron becomes his personal property as "the badge of a Mason." As he advances in Masonry he will receive other aprons of varying types, but never one that equals his first one in the emblematic significance and Masonic value.
There is no one of the symbols of Speculative Masonry more important in its teachings, or more interesting in its history than the lambskin, or white leather apron. Its lessons commence at an early period in the Mason's progress, and it is impressed upon his memory as the first gift which he receives, the first symbol which is explained to him, and the first tangible evidence which he possesses of his admission into the Fraternity. The color of a Mason's apron should be pure and unspotted white. It appears certain that the use of an apron or some equivalent investiture, as a mystic symbol, was common among the ancients, In ancient Israel the girdle formed a part of the investiture of the priesthood, and for the ordinary priest it was of plain white. The superior orders of the priesthood were adorned with highly ornamented girdles. In the mysteries of the Mithras, in Persia, the candidate was invested with a white apron. The Jewish sect of the Essenes clothed their novices with a white robe. Like other portions of the Masonic ritual, the ceremony of clothing the newly initiated candidate with a white apron of lambskin belongs within the veil of antiquity. In the Hebrew religion and in Christianity, even as in many other sects, white has always been an emblem of purity.