Nicene and Post-Nicene Fathers, Vol. II:
On Christian Doctrine: Chapter 15

Chapter 15.—Rule for Interpreting Figurative Expressions.

23.  The tyranny of lust being thus overthrown, charity reigns through its supremely just laws of love to God for His own sake, and love to one’s self and one’s neighbor for God’s sake.  Accordingly, in regard to figurative expressions, a rule such as the following will be observed, to carefully turn over in our minds and meditate upon what we read till an interpretation be found that tends to establish the reign of love.  Now, if when taken literally it at once gives a meaning of this kind, the expression is not to be considered figurative.