White Masonic Lambskin Apron

Operative Freemasonry:  In operative Freemasonry, an apron was worn by operative masons to preserve their garments from stain.

Speculative Freemasonry: In speculative Freemasonry, the apron reminds us that we must keep ourselves away from moral defilement; or in the more figurative language as read in the Holy Scripture; we must keep our garments white and keep ourselves unspotted from the world.

From the New Testament:  "Unspotted From the World" 

James 1:21 - "Lay aside all filthiness and overflow of wickedness."

James 1:26-27:  "If anyone among you thinks he is religious, and does not bridle his tongue but deceives his own heart, this one's religion is useless. Pure and undefiled religion before God and the Father is this: to visit orphans and widows in their trouble, and to keep oneself unspotted from the world."

Gallatians 5:19-21:  "Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness, idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambition, dissensions, heresies, envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God."

The Masonic Lamb:  

Masonic Lamb:  From Albert Mackey's Revised Encyclopedia of Freemasonry, Vol. 1, page 558 and 559, 1929

First Degree:  In Ancient Craft Masonry, the Lamb is the symbol of innocence; thus in the instructions of the First Degree:  "In all ages the Lamb has been deemed an emblem of innocence." 

Hence it is required that a Freemason's Apron should be made of lambskin.  In the advanced Degrees, and in the Degrees of chivalry, as in Christian iconography, or illustration, the lamb is a symbol of Jesus Christ. 

The introduction of this Christian symbolism of the lamb comes from the expression of Saint John the Baptist, who exclaimed, on seeing Jesus, "Behold the Lamb of God"; which was undoubtedly derived from the prophetic writers, who compare the Messiah suffering on the cross to a lamb under the knife of a butcher. 

Paschal Lamb...also called the Holy Lamb:  This was the lamb offered up by the Jews at the paschal feast, (the Passover).  This has been transferred to Christian symbolism, to Easter, and naturally to Chivalric Freemasonry; and hence we find it among the symbols of modern Templarism.

Lamb of God in Christian Art:  The paschal lamb, as a Christian and Masonic symbol, also called the Agnus Dei, or Lamb of God, first appeared in Christian art after the sixth century.  This is depicted as a lamb standing on the ground, holding by the left forefoot a banner, on which a cross is inscribed.

This paschal lamb, or Lamb of God, has been adopted as a symbol by the Knights Templar, being borne in one of the banners of the Order, and constituting, with the square which it surmounts, the jewel of the Generalissimo of a Commandery.

The lamb is a symbol of Christ; the cross, of His passion; and the banner of His victory over death and hell.

Knights Templar Deed:  Barrington states (Archaelogia ix, page 134) that in a Deed of the English Knights Templar, granting lands in Cambridgeshire, the seal is a Holy Land, and the arms of the master of the Temple at London were argent, a cross gules, and on the nombril point thereof a Holy Lamb, that is, a Paschal or Holy Lamb on the center of a red cross in a white field.

End of Albert Mackey's dissertation on the Masonic Lamb

Sacrificial Lamb and the Passover

Long before the Knights Templar, Freemasonry, and even Christianity, itself, existed, we repeatedly read of the sacrificial lamb throughout the Holy Scriptures, beginning in Exodus.  Exodus is the second book as found in first the Torah, and later, in the Old Testament.  The Book of Exodus was written by Moses who lived approximately 1500 years before Christ.

Exodus 12:21:  (from the Torah)

Then, Moses called for all the elders of Israel, and said unto them:  "Draw out and take you lambs according to your families, and kill the passover lamb.

Exodus 12:21:  (from the King James Bible)

"Then Moses called for all the elders of Israel, and said unto them, Draw out and take you a lamb according to your families, and kill the passover."

The name "Passover" refers to the fact that God "passed over" the houses of the Jews when he was slaying the firstborn of Egypt.

Christian Lamb:  For those of the Christian faith, the lamb is a symbol of Jesus Christ and is celebrated at Easter.   

Jewish Lamb of the Passover:  For those of the Jewish faith, the lamb is a symbol of God's mercy and is celebrated each Spring of the year with a special seder (a dinner or feast).

Masonic Lamb:  Like many other Masonic symbols, the Masonic lamb is a symbol which has been brought down to us from the Holy Scriptures.

It represents purity in all forms...physically, mentally and spiritually.