Letter Quotes - page 7
But since, if the usefulness of the legislation, and the sequence and beauty of the history, were universally evident of itself, we should not believe that any other thing could be understood in the Scriptures save what was obvious, the word of God has arranged that certain stumbling-blocks, as it were, and offences, and impossibilities, should be introduced into the midst of the law and the history, in order that we may not, through being drawn away in all directions by the merely attractive nature of the language, either altogether fall away from the (true) doctrines, as learning nothing worthy of God, or, by not departing from the letter, come to the knowledge of nothing more divine.
Origen
When, therefore, as will be clear to those who read, the passage as a connected whole is literally impossible, whereas the outstanding part of it is not impossible but even true, the reader must endeavor to grasp the entire meaning, connecting by an intellectual process the account of what is literally impossible with the parts that are not impossible but historically true, these being interpreted allegorically in common with the part which, so far as the letter goes, did not happen at all. For our contention with regard to the whole of divine scripture is that it all has a spiritual meaning, but not all a bodily meaning; for the bodily meaning is often proved to be an impossibility.
Origen