For many singers, this is the busiest time of the year, filled with holiday concerts, semester-end performances—and, for some, many, many productions of Messiah. For alto, mezzo-soprano, and countertenor soloists, this involves the preparation of showpiece arias from Handel’s oratorio including “But who may abide,” with all of its glory and challenges. The piece appears in Part I of Messiah, and alternates between a pensive, more lyrical, larghetto “But who may abide when he appeareth” section, and a dramatic, coloratura-filled, prestissimo “For he is like a refiner’s fire” section. The contrast between the two sections perfectly encapsulates two very different…