הלכות תפילין ד:ה
(Painting by Lasar Segall)
When a person sees that there is crookedness in his heart, especially when there is a lot of crookedness, Heaven forbid, he must then perceive himself to be like an animal and completely remove any semblance of knowledge or awareness from his mind. He must then rely entirely on faith and carry himself with purity and simplicity alone. He will then merit tremendous awareness of Hashem. This is related to the consciousness of tefillin.