The ALB is a long, white garment, which flows from shoulders to ankles, and has long sleeves extending to the wrists.
The word alb means “white.”
The ALB was a common outer garment worn in the Graeco-Roman world and would be similar to the soutane worn in the Middle East. However, those of authority wore albs of higher quality with some kind of embroidery or design.
Some modern style ALBS have collars which preclude the necessity for an amice.
The spiritual purpose reminds the priest of his baptism, when he was clothed in white to signify his freedom from sin, purity of new life, and Christian dignity.
Moreover, the Book of Revelation describes the saints who stand around the altar of the Lamb in Heaven as:
“These are the ones who have survived the great period of trial; they have washed their robes and made them white in the blood of the Lamb” (7:14).
In the same way, the priest must offer the Mass with purity of body and soul, and with the dignity befitting Christ’s priesthood. The former vesting prayer was:
“Make me white, O Lord, and purify my heart so that being made white in the Blood of the Lamb, I may deserve an eternal reward.”