Bishop Būlus spends much of this work gathering and expounding on the prophecies of the Nativity from the psalms and the prophets as well as collating the Gospel accounts to piece together justifications for the birth of the Saviour. He takes the title “Sun of Righteousness” mentioned in Malachi 4:2 and the enlightenment theology of the Gospel of St John the Divine to link together God’s entering into the world as a man to “illuminate the world.”