Rabbi Shimon ben Mensya says: "Song of Songs defiles the hands, because it is written with divine spirit. And Kohelet does not defile the hands for it is only written through the wisdom of Solomon." They said to him, "But did he write that by himself? Look, it says (I Kings 5:12) 'And he said three thousand proverbs,' and it says (Proverbs 30:6) 'Do not add to God's words!'"
There is something profoundly spiritual about music. When language aspires to the transcendent, and the soul longs to break free of the gravitational pull of the earth, it modulates into song. Jewish history is not so much read as sung. The rabbis enumerated ten songs at key moments in the life of the nation. There was the song of the Israelites in Egypt (see Is. 30:29), the song at the Red Sea (Ex. 15), the song at the well (Num. 21), and Haazinu, Moses’ song at the end of his life. Joshua sang a song (Josh. 10:12–13). So did Deborah (Judges 5), Hannah (I Sam. 2), and David (II Sam. 22). There was the Song of Solomon, Shir HaShirim, about which R. Akiva said, “All songs are holy but the Song of Songs is the holy of holies” (Mishna Yadayim 3:5). The tenth song has not yet been sung. It is the song of the Messiah.