(quote from RealReality.org/Real_Faith_and_Reason_Vol_2_-_Scientia.pdf)

God is real, and we know He’s real because He does what He says He does. He speaks to us. But how does He speak to us? He speaks through Scripture, observation, and every other method mentioned in Scripture. However, when He speaks, He speaks only the truth. When He speaks, He gives us a true premise and a sound basis for thinking. But what if we add to His words or diminish His words through speculative explanations or interpretations? If we add to His words or diminish them, we destroy the true premise. We need that true premise if we’re going to think rationally. So He asks us not to add to His words or diminish His words through theories, unrevealed theologies, or other forms of speculation.

(end quote)