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Hebrews 5:11 - "Concerning this we have much to say which is hard to explain, since you have become dull in your (spiritual) hearing and sluggish (even slothful in achieving spiritual insight)."

They were not in need of hearing aids; rather their inward man had digressed to become insensitive to spiritual things.
The Holy Spirit does not communicate to our head but to our spirit. You can be a believer for years and not develop your spirit....