This ancient Advent hymn may date back to a community of fifth-century Jewish Christians and perhaps was part of their Hanukkah festival. The text does include many elements of the Hanukkah celebration-remembrance of wilderness wandering, darkness and death, but also celebration of light (the use of candles) and, above all, wonderment about the hope for Christ's return ("O").
In this song, it becomes clear that the one waited for is “Emmanuel—God with us.” The confessions of the church are very eager to identify that Emmanuel as the only Son of God “according to his divine nature” (Belgic Confession, Article 10). Heidelberg Catechism, Lord’s Days 11-13, Questions and Answers 29-34 put great effort into explaining why he is called Jesus, Christ, and God’s only begotten Son.