Unlike the Mass, which has its own proper and ordinary chants, the
Divine Office or Breviary is the privileged place for hymns in Catholic
liturgy. In the hours of the Divine Office, a hymn’s images often
announce a particular time of day. The imagery of light, for example,
pervades the Liber Hymnarius, whether it is the light of early
morning, the noontime sun, or the daylight’s fading. Light imagery
likewise pervades the scriptures, most notably as a metaphorical name
for Jesus Christ, the light of the world.