"To sing is to pray twice." - Saint Augustine
I've always thought of church choirs as small groups, in a way - a community, a fellowship, a place to come together. Choir gives people a place to sing and make music, yes, but also feel safe, be vulnerable, and supportive as we carry one another's burdens.
This is one of the reasons why I feel it's important to end each rehearsal with prayer.
I grew up singing in a fairly large choir in a Methodist church in Georgia (I say "grew up" because I joined when I was 11!). At the end of each rehearsal, we put down our folders, joined hands, and made a circle around the choir room. We stood there for a few moments, sharing joys and concerns with one another and closing our time together with prayer. It was meaningful to me then and has stayed with me; it's a tradition I've carried with me to all the churches I've served.