The Mystic Chorale, one of Greater Boston's favorite community choruses, presents its annual Gospel concert. Led by award­-winning gospel director Jonathan Singleton, the 250­-voices­-strong chorale and 5-piece band present two joyful and spirit-filled performances featuring eclectic music rooted in the African American gospel tradition. The stirring program of contemporary and traditional music includes the moving God Bless the Child; the Soweto Gospel Choir’s Avulekile Amasango combined with Bob Marley’s One Love; the foot-stomping Old Landmark from Aretha Franklin’s Amazing Grace album, and songs by other great gospel artists such as…