The following article was written by Bro. Joe Lane Field, P.M. and published in Winter 2010 edition of New Mexico Freemason
THE LAMBSKIN OR WHITE LEATHERN APRON
The Masonic apron is a pure white lambskin, from fourteen to sixteen inches wide, and from twelve to fourteen deep, with a fall about three to four inches deep; square at the bottom without ornament. It is a perfect rectangle and the angles represent truth and honesty. Its four sides remind Masons to practice the four cardinal virtues: temperance in word and act; fortitude in a noble purpose; prudence in judgment; and justice to the humble and great alike.
The flap is triangular and its three sides refer to the three attributes of God - infinite knowledge, infinite power, and infinite presence. The two strings remind us that reverence of the practice of Masonic virtues should be bound to the heart and conscience by the double ties of love to God and man. The apron with its four sides and the flay with its three constitute the sacred number seven. Seven refers to the seven liberal arts and sciences which were the foundation of Masonry.
The lambskin or white leathern apron is the badge of a Mason, and the first gift bestowed by the Worshipful Master upon the newly initiated Entered Apprentice. The apron is worn by operative Masons, to preserve their garments from spot or stain. But we, as speculative Masons, use it for a more noble purpose. By the whiteness of its color, and the innocence of the animal from which it is obtained, we are admonished to preserve that blameless purity of life and conduct, which alone will enable us hereafter to present ourselves before the Grand Master of the Universe, unstained with sin and unsullied with vice.
There is no other “badge of a Mason”. A man who is not a Mason may cover his coat with pins, wear a Masonic ring, or hang charms of square and compasses all over his attire, with never a right so to do. He can obtain that right only in a lodge, and he cannot receive - at any other hands - a lamb skin apron with any meaning attached, except in a Masonic lodge.
The apron, among many things, is a symbol of innocence, purity, and honor. In ancient times, it was a badge of distinction. None but the members of the Jewish priesthood could wear one. It is still a badge of distinction. Not all men are permitted to wear the Masonic apron. That right is conferred upon you in the Rite of Investiture - when the Worshipful Master presents you with a lambskin or white leathern apron.
As a badge of antiquity, your aprons puts emphasis on the value of the past, and its contribution to the present and future happiness of man. The symbolism of your apron has come out of the mist of time. It has been tested by men of religion as well as laboring men. As it was worn with honor by the Operative Mason, so must it today by the Speculative Mason.
The Masonic Apron will only be honorable if it is worthily worn. You have proven your right to wear it by being tried and tested. You must continue to prove you are worthy of wearing it by putting into practice the lessons, teachings, and philosophy of the Order.
Hence the ceremony of the Rite of Investiture becomes a real worth; only less than that of your Obligation, it puts the sign and seal of value upon that which has been, up to now, a pledge of the word and an obligation of the spirit. The ceremony is of vital importance, for here at last is a visual, physical evidence that you are approved by your fellows. You have passed the scrutiny of a committee, you have passed the ballot of your lodge; you have been found worthy, well-qualified, duly and truly prepared; and the apron has been presented to you as the sign and seal of the fraternity that these are accomplished facts.
Lastly, there is a singular, peculiar significance of the Masonic apron. It is the first symbol of Masonic life and also the last. It is impressed upon your memory as the first gift you receive, the first symbol which is explained to you, and the first tangible evidence which you possess of your admission into the fraternity. The mean and significance of the apron becomes something that binds you to God, your individual religious beliefs, and our Masonic traditions.