Heidegger's Bible Handbook: Song of Songs: Argument of the Song
3. The Church of Christ in this life is being prepared like a chaste virgin for Christ. Thence the argument of the Song is explained. It is an Epithalamium of the nuptials of Christ and the Church.
Saint Paul in 2 Corinthians 11:2 testifies that he burns with zeal for God, that he might present the believing Corinthians to one husband, even Christ, as a παρθένον ἁγνὴν, chaste virgin. Therefore, thus the Church of Christ, and the believing individuals in her, in this temporal life, by the Spirit and word of God are prepared as a virgin and Bride for Christ the Bridegroom, and so for the celebration of the marriage of the Lamb, especially in Heaven, with ineffable joy. The betrothal is contracted in the present temporal life; the marriage is consummated in eternity. But, just as the Bridegroom is borne with the greatest love and affection towards his Bride even before marriage, whether in matter favorable or adverse: so Christ pursues the Church, His Bride, with the most intense love, even in this life, and shares a common sense of joy and sorrow with her, enlarges her joy in favorable matters, and diminishes her sorrow in adversities. But this love of Christ the Bridegroom towards the Church, His Bride, and the mutual love of the latter for the former, and this most vehement and Divine passion, the Song represents, and depicts in living colors, as it were. This is the scope of the book, this the sum, with all the pious consenting. And with good reason does the Most Learned Junius observe that set forth in this book is the manner of Spiritual Betrothal, into which Christ entered with the Church yet living in the world. And Saint Jerome distinguishes it as an Epithalamium, or marriage song, written after the manner of a drama.
Dr. Dilday's Lecture: "The Curious Case of the Song of Solomon"