Lawrence Boadt provides this excellent, though brief, introduction to the Song of Songs:
The third book attributed to Solomon is the Song of Songs, mainly because his name is mentioned in chapters 3 and 8. In both cases he seems more of a model to follow than an author, and we can safely say that the famous king did not write these songs. Like so many other wisdom books, The Song of Songs shows signs of being worked and reworked through many centuries. At the oldest level are love poems, perhaps wedding songs, many of which could go back to the time of Solomon. At the latest level are Persian and Greek phrases that indicate additions made after the exile. There seem to be hints of a dialogue between a young lover and his beloved (bride?), and perhaps even a chorus of the daughters of Jerusalem. At least the tradition identifying different speakers goes back to the Greek translations before the time of Christ. But there is not enough unity among the different songs to say more than that it is a collection extolling the undying power of love between two people.
The close parallels between the language of The Song of Songs and Arab wedding songs from Syria were discovered in the late nineteenth century. The wedding customs included a dance with a sword by the bride on the day before her wedding in which she described her own beauty (Song 1:5; 2:1). For the week after the wedding, the couple is treated as a king and queen with much feasting and still more songs extolling the bride’s beauty (Song 4:1-15; 5:10-16). Such village customs last over many centuries and can help us discover the original setting and use of the Song of Songs. The religious use of such love songs may even go back to the hymns and ceremonies surrounding the sacred marriage rituals of the Canaanite followers of Baal. Certainly, Israel was not the only ancient nation to sing the beauties of the female body (and sometimes of the male). We have examples from both Babylon and Egypt (see ANET 467-69), and Psalm 45 is also a wedding psalm.
But the lusty nature of the songs gave scandal to many of the Jewish rabbis, and as late as the second century A.D. they still had not fully agreed that the book should be in the sacred canon. One of the deciding factors was the belief that it described allegorically the love of Yahweh for Israel as a beloved bride. The Christian Church accepted it quickly for the same reasons—it could easily describe in allegory the love of Christ for the Church, or for the soul of the believer. St. Bernard of Clairvaux in the twelfth century wrote a great number of sermons on the Song of Songs describing the love of Christ for the soul and the mystical union that came from this love. They habve become the classic source of such a mystical spirituality. Other Christian writers of the Middle Ages saw an allegory of Christ’s love for his Blessed Mother. In all of these cases, the later interpretations have gone far beyond the original Old Testament book with its rather graphic desciption of sexual love as a joyful and positive ideal. But they also underline the power of the book to lead people in all ages to discover that love, sexuality, and creation are gifts of God’s goodness.