The following is from Adam Clarke’s commentary on the Song of Solomon. Although he was referring specifically to that book, I think it pays to remember these words when attempting to over-allegorize any book of scripture.
In the preceding notes I have carefully avoided all attempts to spiritualize this song. My reasons I have already given in the introduction; and in the course of writing these short notes I have seen no cause to alter my opinion. Any man may allegorize it; that is an easy matter; for when he once considers it to be an allegory, his own creed will furnish him with enough to say, write, or preach, upon the spiritual meanings of every part, which will be an exhibition of his own confession of faith! But when he has finished his work, the question will recur, By what authority do you give it these meanings? And till the day of judgment none shall be able to say, “I have the authority of God for my exposition.”