We have recently spoken about the roles of altar server and acolyte. You may have noticed that while our senior servers and acolyte have typically worn albs, our junior servers are now also wearing albs, replacing the red cassock and white cotta they wore previously.
Sometimes people may comment when lay ministers are wearing albs that they are wearing “priest’s clothes”. Priests certainly do wear albs, and are required to do so, but they are not a garment that belongs solely to ordained ministers.
The alb is a sign that the one who wears it has been baptised. The alb is (at least in a larger form for us baptised as babies) the white garment in which we are clothed when we are baptised, “the outward sign of our Christian dignity.” This is why Damian, Lona and Laime were clothed in albs once they were baptised at the Easter Vigil a month ago. In fact, all of us could wear an alb at Mass if we wanted to, but it is probably easier for us all to stick to our “Sunday best” (and trust me, Sunday best is much cooler in the summer!).
The priest puts on the alb first when vesting for Mass because he is, firstly, a baptised Christian. Next, he puts on the stole (the coloured strip of cloth worn over the shoulders) as a sign that he is ordained. Finally, he puts on the chasuble (the coloured outer garment we can see) as a sign that he is a priest entrusted with the duty of celebrating the Eucharist.
The vestment proper to the priest celebrant at Mass and other sacred actions directly connected with Mass is, unless otherwise indicated, the chasuble, worn over the alb and stole. Acolytes, lectors, and other lay ministers may wear the alb or other suitable vesture that is lawfully approved by the Conference of Bishops. (General Instruction of the Roman Missal, articles 337, 339)