[This was written ages ago for my thesis, but hasn't made the cut, but didn't want to lose it, so now you get the benefit. :-) Let me know what you think.]
Paul’s writings are crammed full of metaphorical language. The difficulty with interpreting any analogy is determining which aspects of the analogical image hold to the referent and which do not. This process of interpretation frequently takes place on the subconscious level in all levels of communication. Whether it is the advertising tag line, “Red Bull: it gives you wings,” or the Church congregation praying to “Father God,” interpretation is instant and subconscious. We know without being told that we will not be able to fly as result of the caffeine drink and that God is not our biological progenitor. By necessity metaphors involve the recipient in an act of interpretation that comes naturally but is fraught with potential danger. From the point of view of classical theology ‘metaphors are conceptually unclean’ because they are generally open to multiple and conflicting interpretations.
Susan Eastman provides a useful typology for approaches to the abundance of metaphor in Paul. Firstly, one may focus on one metaphor and ‘collapse’ the ‘distinction between the subject and the image’. This literalizing of one metaphor inevitably takes place at the expense of other imagery which becomes subservient. Eastman, discussing metaphorical perceptions of God, considers this collapse a work of idolatry. In Paul's ecclesiology (for example) such a collapse simply obscures the author’s intention in providing us with many images and not one.
Secondly, one may translate metaphors into ‘a different linguistic medium,’ that is into more conceptually precise language, with the goal of allowing contemporary understanding. Eastman takes issue with the approach of both Engberg-Pedersen and Bultmann who respectively translate or demythologize the language of religious experience into ethics. Eastman rightly objects that religious experience cannot be simply equated to ethics and that as descriptions of religious experience they provide the most substantial and relevant link between the historical Paul and his contemporary readers. I would add to this that flattening out of metaphors into precise propositional concepts inevitably results in a loss of significant information, especially at the illocutionary and perlocutionary levels.
Thirdly, one may acknowledge the metaphor’s ability to evoke a wide and deep reaction in receiver of the text. For Eastman, Paul’s metaphor’s functions not as a barrier to communication but ‘rather as a vehicle that connects the text with the contemporary reader on a multitude of levels.’ It is this approach which potentially yields the most fruit in the study of Paul's metaphors, assuming that: 1) Paul would not have used many metaphors if he only intended one, 2) if Paul had intended to communicate precise concepts he would have used appropriate language. The understanding that for Paul metaphors are evocations of religious experience rather than clumsy methods of asserting propositions (ethical, theological or otherwise) is enourmously significant for the task of both the historian-exegete and the modern interpreter.
 Richard D. Patterson, “Metaphors of Marriage as Expressions of Divine-Human Relations,” Journal of the Evangelical Theological Society 51, no. 4 (December 2008): 689.
 Kevin J. Vanhoozer, Is There a Meaning in this Text (Grand Rapids: Zondervan, 1998), 133.
 Susan Eastman, Recovering Paul's mother tongue : language and theology in Galatians (Grand Rapids Mich: Eerdmans, 2007), 189-93.
 Ibid., 189-90.
 Ibid., 190-1.
 Ibid., 192-3.