As a result, Crane's moral reflections range from the pre-ethical (duties toward animals) to the properly ethical (conduct toward humans in ordinary situations) to the optional and supererogatory (heroic actions above and beyond ethical obligation).
-- Patrick K. Dooley, "The humanism of Stephen Crane", The Humanist, January 11, 1996
He deemed the leading of an ascetic life ultimately as a supererogatory act, since baptism was the sole criterion by which one's Christian identity could be defined.
-- Willemien Otten, "Augustine on marriage, monasticism, and the community of the church", Theological Studies, September 1, 1998
Remember that Stencil has not given up his search for further evidence at the novel's end, but that evidence, while adding possible refinement to his thesis, has become supererogatory to the proof of its overall correctness.
-- Kenneth Kupsch, "Finding V", Twentieth Century Literature, December 22, 1998
The interpretive stance here is complex, persuasive, and for the most part refreshingly free of supererogatory theoretical gestures.
-- Alice Falk, "Victorian Poetry: Poetry, Poetics, and Politics", College Literature, June 1, 1995
The best opera directors accept this primacy of music in creating theatrical illusion; the worst ones swamp it with overblown stage effects which make the music, as it were supererogatory.
-- Terry Teachout, "Words, music, opera", Commentary, December 1, 1995