In Galatians 4, Paul uses two women to talk about two covenants, and he qualifies it by saying “This is allegorically speaking” (Galatians 4:24). This passage is sometimes used to show how the NT uses the OT non-literally.* It is therefore used to give license to the modern interpreter to also use the NT non-literally.
Have you ever thought about why Paul said, “This is allegorically speaking”?
Might it be because had he not qualified it, no one would have caught it?
Had Paul’s method been as standard as some would have us believe, there would be no need to say it. But because Paul was doing something out of the ordinary, he said it in order to keep the readers from treating the text literally, just like they were accustomed to doing.
So far from a license to use the OT non-literally, it is actually a reminder not to use it non-literally.
*“Literal” means normal, as opposed to literalistic. Literal recognizes the use of figures of speech, but recognizes them as figures of speech.