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The context in Isaiah does not support your wild assertion.
It is not about the meaning of scripture, but about convincing the unbelieving.
It demolishes your whole plan.
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The distinction you offer is of little consequence in that the passage has God calling on human reason as guide leading toward faith. Again, I suggest that this supports teachings that faith and reason are meant to be allies, not adversaries, and that even those without faith may nevertheless distinguish good and evil.