The final tercet within the sestet declares that this
phenomenon is not a “wonder,” but rather an everyday occurrence—part
of what it means to be human. This striving, far from exhausting
the individual, serves to bring out his or her inner glow—much as
the daily use of a metal plow, instead of wearing it down, actually polishes
it—causing it to sparkle and shine. The suggestion is that there
is a glittering, luminous core to every individual, which a concerted
religious life can expose. The subsequent image is of embers breaking
open to reveal a smoldering interior. Hopkins words this image so
as to relate the concept back to the Crucifixion: The verb “gash”
(which doubles for “gush”) suggests the wounding of Christ’s body
and the shedding of his “gold-vermilion” blood.