In the first volume of the Theological Dictionary of the New Testament, Friedrich Büchsel notes how “allegorical exposition” is common among ancient people including “Indians, Mohammedans, Greeks, Jews and Christians.” In particular, allegorical interpretation arose when something in the text brought modern offense, as is the case of Homer. This too carried over in Christian interpretation. Where various Old Testament texts seemed to oppose accepted theology, allegorical interpretations were made to smooth out the differences. Büschel notes, “In method, . . . the Jewish and Christian interpretation of the OT is dependent on this allegorical exposition of Homer.”
Büschel goes on to report Aristobulus as the first Jewish interpreter to adopt an allegorical approach and he learned it from the Greeks: “It can hardly be doubted that he took over the allegorical method from the Greeks, for he is saturated with Greek culture and uses the same method to interpret Greek poetry.” Still, the greatest name associated with allegory is that of Philo. Philo may have been influenced by Greek culture but never at the expense of the literal sense. If anything, he upheld the literal sense of the Law and then went beyond the literal sense. This kind of polyvalent approach adumbrates that of other known ‘allegorists’ like Origen. In his own day, Büschel calls Philo “a theologian of the centre who avoids extremes and can combine diverse elements.” In fact, it would be misleading to label Philo an extreme if that implied he forsook the legal requirements of the Law. Rather, as Büschel concludes,
In this matter we should bear in mind the highly complicated nature of Philo’s theology. It maintains an artificial balance between a legal and literalistic Judaism on the one side and an intellectual and spiritualistic mysticism on the other, never inclining too much to either the one or the other, but keeping the two in equilibrium.
While Greek approaches to literature influenced Aristobulus and Philo, it also impacted the Jews in Palestine. For instance, one positive fruit of this allegorical approach was the inclusion of Song of Songs in the canon. “Only by means of allegorising could this collection of love songs be understood as a representation of the love which binds Israel to God.” Additionally, the nature of “allegory” is different in Palestine. “Among the Palestinians allegorical interpretations are both rarer and less arbitrary; the distance between the literal meaning and the allegorical is much less.” This difference stems from the Palestinians distance from Greco-Roman philosophy and from their closer adherence to the text. Nevertheless, it is apparent that among Jews there is a polyvalent approach to the text (“For the Palestinians, too, it is in keeping with the dignity of Scripture that it has many meanings”), and thus an openness to reading the Scriptures allegorically.
That being said, there was also an awareness that the text of Scripture was written allegorically, as Josephus says of Moses. In Antiquities, the Jewish historian says,
I exhort, therefore, my readers to examine this whole undertaking in that view; for thereby it will appear to them that there is nothing therein disagreeable either to the majesty of God, or to his love to mankind; for all things have here a reference to the nature of the universe; while our legislator speaks some things wisely, but enigmatically, and others under a decent allegory, but still explains such things as required a direct explication plainly and expressly. 
The Legislator is Moses, whom Josephus describes as writing something under an allegory, a point that returns us to Galatians 4:24. For Büschel, he does not see allegorical interpretation in the Gospels, but he does believe Paul engaged in Palestinian-like allegory. That is, in expounding the Old Testament text he allegorized the leaven in 1 Corinthians 5:6–8, the ox treading out the grain in 1 Corinthians 9:8–10, the water-giving Rock in 1 Corinthians 10:1–11, and the two women as two covenants in Galatians 4:21–31. He writes of Paul,
He expounds Scripture as one who lives in the time of its fulfilment (1 C. 10:11), as one for whom the veil is thus removed which had previously lain over its reading (2 C. 3:14), so that the true sense of the OT may now be seen. Allegorising is thus a means to carry though his understanding of Scripture in terms of the centrality of Christ or the cross.
In this regard, Büschel concludes that Paul engaged in allegorical interpretation, i.e., “to explain or denote [something] allegorically.” Interestingly, this contradicts his opening explanation of Galatians 4:24, which he asserts is a case of reading Genesis as written allegorically. If Moses spoke allegorically in Genesis or at least employed figurative patterns to contrast Sarah and Hagar, then Paul is only observing what is in the text, not what Paul invents in his mind. Surely, more needs to be said, but Buschel’s terse treatment of Paul is insufficient to label his quotations of the law allegorical. There may be some surface similarities, but it is not the same thing.
And thus in Galatians 4 and in the book of 1 Corinthians we should labor to see what Paul saw in the text of Moses and how it now applies to the church on whom the end of time has come. If Büschel is right, Paul actively allegorized, at which point we must decide if we can do that or not in our interpretation. However, if he did not invent allegories, but saw in Moses patterns, types, and shadows which are now fulfilled in Christ, then we must follow him in his interpretation strategy, because he is teaching us how to follow the text of Scripture from Moses through the Prophets to Christ and his Church.
Indeed, this I believe is what Paul was doing. And in the next few days I’ll share a few more reflections on Galatians 4:24 and how to best understand Paul’s reading of Moses.
Soli Deo Gloria, ds
 Büchsel, F. ἀλληγορέω. G. Kittel, G. W. Bromiley, & G. Friedrich (Eds.), Theological dictionary of the New Testament (electronic ed., Vol. 1, p. 260). Grand Rapids, MI: Eerdmans.
 Ibid., 260–61.
 Ibid., 261.
 Ibid., 262.
 Ibid., 263.
 Josephus, F., & Whiston, W. (1987). The works of Josephus: complete and unabridged (p. 28). Peabody: Hendrickson.
 Büchsel, 263.