In some places the Lord showed what happens if He is understood too literalisticly, as in the case of the leaven of Pharisees. But even in other stories, about the poor, or about hating one's mother and father, or even making oneself enuch, is it not clear that the Lord was referring to the spiritual things?
No one here denies the use of idioms, metaphors, hyperbole, analogies, symbolism, or other figures of speech. Scripture plainly contains all of those things.
What we deny is the idea that the existence of figurative language gives us permission to spiritualize any passage that conflicts with our theology.
There are objective ways to recognize figures of speech. Context matters. Grammar matters. Genre matters. Audience matters. Literary structure matters. Hebrew idioms can often be identified. Poetic language has recognizable characteristics. Hyperbole, metaphor, analogy, and symbolic imagery all have contextual indicators that distinguish them from straightforward propositional statements.
The proper question is not, “Does this passage fit my doctrine?” The proper question is, “What did the author intend to communicate?”
Once a person adopts the method of spiritualizing passages merely because the plain meaning creates theological tension, interpretation ceases to have rules. The text no longer governs the doctrine. The doctrine governs the text.
That approach becomes infinitely elastic. Any passage can then be transformed into meaning its opposite simply by appealing to some deeper “spiritual” interpretation that exists nowhere in the grammar, nowhere in the context, and nowhere in the author’s intent.
Ironically, the examples you mentioned actually prove the point rather than undermine it. The disciples misunderstood the “leaven of the Pharisees” precisely because Christ Himself clarified that He was speaking metaphorically. The surrounding context identified the figure of speech. Likewise, statements about hating father and mother, or plucking out an eye, contain obvious hyperbolic and comparative language consistent with well known Jewish rhetorical forms.
None of that establishes a license for uncontrolled allegorization. Quite the opposite. It demonstrates that figures of speech are understood through contextual and grammatical indicators, not through theological convenience.