Guard your thoughts carefully, for thought can literally create a living thing.

The higher a faculty, the further it can reach.

You can kick something with your foot, but throw it higher with your hand. You can reach still further with your voice, calling to a person very far away.  Hearing reaches yet further, for you can hear sounds like gunfire from a very great distance.  Your sight reaches even further, seeing things in the sky.  The higher the faculty, the further it can reach.  And the highest of all is the mind, which can penetrate the loftiest heights.

You must therefore safeguard your mind above all else.  ~ R’ Nachman of Breslov zt”l