The “inner ear” Jesus speaks about is the voice of your spirit. A “born again” individual has a recreated human spirit.
You know John 3:16 but do you know John 3:6?
“That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.” (Jn 3:6)
That which is born of natural man is a natural man but that which is born (or re-created) by the Holy Spirit is your human spirit. Notice the capital Spirit and the lower case spirit.
Your spirit man is your inner ear. Your natural eyes are flooded with sight and your natural ear with sound… but in the DARK, Jesus said, it’s different. Jesus said His voice is heard in the night. Why? It’s easier to hear the inner voice with the inner ear when the outer world is silent. This is both symbolic language and perhaps to an extent, literal.
Many a preaching giant was formed in the light-less dungeon of despair.
When all is seemingly darkest, the light dawns. It’s when you are pushed down, driven back, even booed off stage that you find the inner power to hear what you’ve needed to hear all along. Once you give utterance to the thing you hear in the dark, you shift gears and become A VOICE!