st. l = Ex. 15:1-2
This triumphant text paraphrases the beginning of the Song of Moses and Miriam in Exodus 15, which was identified in the medieval church as one of the "lesser" Old Testament canticles. The song celebrates the LORD's victory over the Egyptians after the Israelites crossed the Red Sea (Sea of Reeds). Jewish tradition calls for using the Song of Moses each Sabbath evening to commemorate the Exodus. The anonymous versification (including the optional Easter stanza) dates from the mid-twentieth century.
As a brief chorus or a canon by itself; possibly as a frame around another hymn. The Easter stanza may be sung with stanza 1 (especially during Easter Vigil), by itself, or as a frame around "Christ the Lord Is Risen Today" (388).
--Psalter Hymnal Handbook