Rabbi Yosef Yitzchak of Lubavitch (1880-1950) told:
“It was summer of 1896, and father and myself were strolling in the fields of Balivka, a hamlet near Lubavitch. The grain was near to ripening, and the wheat and grass swayed gently in the breeze.
“Said father to me: ‘See G-dliness! Every movement of each stalk and grass was included in G-d’s Primordial Thought of Creation, in G-d’s all-embracing vision of history, and is guided by Divine providence toward a G-dly purpose.’
“Walking, we entered the forest. Engrossed in what I have heard, excited by the gentleness and seriousness of father’s words, I absentmindedly tore a leaf off a passing tree. Holding it a while in my hands, I continued my thoughtful pacing, occasionally tearing small pieces of leaf and casting them to the winds.
“ ‘The Holy Ari,” said father to me, ‘says that not only is every leaf on a tree a creation invested with Divine life, created to specific purpose within G-d’s intent in creation, but also that within each and every leaf there is a spark of a soul that has descended to earth to find its correction and fulfillment.
“ ‘The Talmud,’ father continued, ‘rules that “a man is always responsible for his actions, whether awake or asleep.” The difference between wakefulness and sleep is in the inner faculties of man, his intellect and emotions. The external faculties function equally well in sleep, only the inner faculties are confused. So dreams present us with contradictory truths. A waking man sees the real world, a sleeping man does not. This is the deeper significance of wakefulness and sleep: when one is awake one sees Divinity; when asleep, one does not.
“ ‘Nevertheless, our sages maintain that man is always responsible for his actions, whether awake or asleep. Only this moment we have spoken of Divine providence, and, unthinkingly, you tore off a leaf, played with it in your hands, twisting, squashing and tearing it to pieces, throwing it in all directions.
“ ‘How can one be so callous toward a creation of G-d? This leaf was created by the Almighty towards a specific purpose and is imbued with a Divine life force. It has a body and it has its life. In what way is the “I” of this leaf inferior to yours?’”
 Kabbalist Rabbi Isaac Luria, 1534-1572.
 Talmud, Bava Kama 3b
 I.e. cardiac and respiratory functions, digestion, cell replenishment, etc.