From a reader…
It is my pastor’s practice to wear only the alb and stole when he says Mass on weekdays. I find this very distracting and irreverent. Is a priest required to wear a chasuble when saying Mass?
Is your parish is so poor that it cannot afford a chasuble? Perhaps a gift from a wealthier parish can be arranged.
The ever useful document from the CDW Redemptionis Sacramentum helps us out with this question.
4. Liturgical Vesture
[123.] “The vestment proper to the Priest celebrant at Mass, and in other sacred actions directly connected with Mass unless otherwise indicated, is the chasuble, worn over the alb and stole.” Likewise the Priest, in putting on the chasuble according to the rubrics, is not to omit the stole. All Ordinaries should be vigilant in order that all usage to the contrary be eradicated. [So, this says that the local bishop needs to make sure that priests are properly dressed for Mass. How odd that that should be necessary, but apparently some priests think they are so wonderful that they can ignore these important requirements.]
[124.] A faculty is given in the Roman Missal for the Priest concelebrants at Mass other than the principal concelebrant (who should always put on a chasuble of the prescribed colour), ….
The rubrics are clear. Weekdays or not, a chasuble is required for the celebration of Mass.
If (when), however, Father is to offer Holy Mass in a prison camp, as many priests may be doing in the near future, he will have to make do with what he has.
Meanwhile, before contacting anyone else (such as the local Bishop – see above), Father should be urged not to go out to say Mass half naked.
It’s embarrassing for everyone!