This quote regarding Luther's commentaries on Ecclesiates and Song of Solomon interested me today. From pages 247 to 250.
From 30 July until 7 November 1526, Luther lectured on Ecclesiastes. Because of linguistic problems the task proved to be so difficult that he almost lost interest and patience. Therefore he interrupted his lecturing between 5 September and 25 September. To that point Luther had had no commentaries on Ecclesiastes he could use. Presumably it was because of this that he had selected this particular book fo the Bible. According to Ecclesiastes, existing circumstances had to be accepted in and despite their "nothingness." But this was not to be understood in the previous sense of a monastic despising of the goodness of creation in itself, but as a criticism of the way human beings dealt with it. Thus Luther, for example, expressly approved of research into nature. It was fear and dissatisfaction that made the world empty and void. Ecclesiastes' theme was the false and senseless efforts of men. Luther was thus able to understand this book of the Bible as instruction for political life. Here he was not looking at specific individual rules--they came from human common sense--but at continuing distressing circumstances. Ecclesiastes taught a liberating acceptance in the world, analogous to the freedom of conscience that the gospel brings. Such acceptance did not keep one from taking action in education or polictics; however, one should trust in God while attempting it. Thus the two sidetracks of presumptuousness and despair might be avoided and what was right could be done. This expressly contradicted the misunderstanding--one that frequently arises--that there was a moral quietism among the evangelicals.
... Luther rejected the current interpretation of the Song of Solomon as a love song or as an allegory of the relationship between Christ and the church. He understood it, analogously to Ecclesiastes, as a hymn of praise and thanksgiving over politics, which could be pursued properly and peacefully only in connection with God. As unique and interesting as the idea may have been of a prince who ruled in accord with God, as one did in Electoral Saxony, it was mistaken; the text, which Luther characterized as courtly language, did not permit this incorrect interpretation. Love and political affairs were not the same thing at all. It is unfortunate that Luther the exegete did not want to accept the erotic sense of the Song of Solomon. At any rate, however, he was not entirely confident of his own interpretation. At the conclusion of the work, which was not printed until 1539, he mentioned the possibility of error, and he hoped that people would have patience with his efforts, for the commentaries of others appeared far more unsatisfactory to him.