For though the Carmelites did sing the Salve Regina on the way to the scaffold…the Salve Regina did not actually accompany the decapitations. Their final song at the scaffold – for there were several – was Psalm 117, Laudate Dominum omnes gentes, which proclaims the mystic truth couched at the heart of the Christian experience of salvation: God’s mercy is at the center of all things, even of being guillotined…
Spontaneously bursting from the lips of Sister Constance as she, designated as the first to die, started up the scaffold steps, the austere chanting of the psalm was in fact taken up and carried forward by the others until the end. Thus as the implacable blade cut short each nun’s voice and her head with an effusion of blood, the chanting of women’s voices insistently proclaimed before men and angels (1 Cor 4:9) that God’s mercy was being confirmed on them.
Such was their final statement, their final word, their final witness. No protest was lodged against the new totalitarian terrorist government, no denunciation of its disgusting daily cult of blood sacrifice. No complaint at this ultimate moment came from these defenseless, dispossessed, and unjustly persecuted Christian women that their most basic human rights were being grossly violated even as the new order celebrated its Declaration of the Rights of Man. Naught but their austere chant of high, solemn joy that, after some 20 months of daily consecrating themselves for this hour, God’s mercy was allowing them to make their act of holocaust to restore peace to France and her Church.
William Bush, To Quell the Terror: The True Story of the Carmelite Martyrs of Compiegne (1999)