Dealba me, Domine, et munda cor meum; ut, in Sanguine Agni dealbatus, gaudiis perfruar sempiternis.
Make me white, O Lord, and cleanse my heart, that being made white in the Blood of the Lamb, I may thoroughly rejoice in eternal joy.
The syntax here has it that the Lord’s action of sanctifying grace wrought in heart and soul by the Blood of the Lamb will bring us to rejoice exceedly forever in heaven.
One thinks immediately of the transfiguration of our Lord, and His discussion with Moses and Elijah about His Exodus, His death and Resurrection in Jerusalem. No fuller on earth could make that “alb” that our Lord wore more resplendant, more glorious, manifesting as it did, the glory of that greatest of all acts of love coming up for Him in Jerusalem, on the Cross.
One also thinks of the burning ember carried by the angels to the lips of Elijah, that he might be rendered worthy of his most awesome mission of in-your-face prophesying. But I digress.
The “alb” is the priestly linen worn from the time of Aaron until today. It is worn by our Lord. It is the corporal used at Mass.
This is the baptismal robe of the newly baptised, from the early days of the Church until today.
Again, it is about our Lord Jesus, with His face set on going to the cross, on going to the mountain of God, to the Last Supper, to Calvary. What a great preparation for Mass to recite this little prayer while vesting!