Lambskin refers to the material specifically required for the Masonic apron, which is a significant symbol in Freemasonry. The apron must be made of lambskin as no other material, such as linen, silk, or satin, could adequately convey its symbolism. The lamb is traditionally seen as an emblem of innocence, a concept deeply rooted in both Jewish and Christian traditions. For instance, in the Old Testament, lambs were used for sin and burnt offerings, while in the New Testament, the term 'lamb' often symbolizes innocence and purity. The paschal lamb, for example, is associated with Christ, referred to as the 'spotless Lamb of God' who was sacrificed for humanity's sins. Thus, the lambskin apron symbolizes purity and the moral and physical qualifications necessary for participation in Masonic rituals. It is also a badge of service and integrity, marking the wearer's commitment to the principles of Freemasonry.