Likutei Moharan 225:1/ליקוטי מוהר"ן רכ״ה:א׳

1Know! when the lungs are perfect, it causes trust to be perfect. For in the main, trust is perfected by means of the intellect, as it is written, “Everyone’s eyes look to You in hope” (Psalms 145:15). “Eyes” are the aspect of the intellect, as it is written, “The eyes of both of them were opened” (Genesis 3:7) ; and Rashi comments: This is said with respect to wisdom (loc. cit.).

2Thus, commensurate with one’s intellect is one’s trust. This is because there are many degrees and levels of trust, ad infinitum, corresponding to “Trust in God forever and ever” (Isaiah 26:4). Yet, everything is commensurate with the intellect, as mentioned above.

3And the intellect primarily depends upon the lungs. The reason is that the intellect depends upon the moisture that rises to the brain, this being the aspect of oil. The brain itself is the wick, and the soul [seated] in the brain is the light. Thus it is that the intellect is maintained primarily by the moisture of the body. And the moisture itself depends upon the lungs, as is brought, “If not for the lobes of the lungs fanning the heart, the heart would consume the entire body” (Tikkuney Zohar #13, p.28a). This is the aspect of (Exodus 25:20), “The cherubs will have their wings spread over the KaPoReT (covering)”—the KaPuRTa (cover) of the heart (Zohar III, 234a).

4Thus it is that through the lungs the moisture is maintained and is not dried out by the heart. This maintains the intellect, which is the aspect of a lamp fueled by the moisture, as explained above. And it is through the intellect that trust is produced, as explained above. We may conclude, therefore, that the perfection of trust is dependent upon the perfection of the lungs.