1) The first level of excitement is the arousal of the Divine soul as it is invested within the animal soul. This is called the “external man” of the “Tzelem Adam (The form of man”). This arousal of the Divine soul causes an excitement of the animal soul too, and corresponds to the first general level of the arousal of the animal soul, as mentioned above, in which a person becomes aroused by the G-dliness vested in the length of the explanation of the creation of all the worlds from the G-dly “nothingness”, which brings them into existence (as explained in Part One). The more he delves and contemplates into the particulars of this matter, the more he becomes aroused. Nonetheless, he does not sense and feel the essence of the created.
2) The second level of excitement is the excitement of the Divine soul itself, as it spreads forth into the body. This means to say that unlike the above level, it is a ray of the Divine soul itself which does not become invested in the body, but shines forth, as it is. This is called the “intermediary man” of the Tzelem. This arousal comes about because he sees the essence of the G-dly light which is invested in the general point of the concept, and corresponds to the second general level of the arousal of the animal soul, as explained above. This means that he sees the essence of the G-dly light which brings about the entire chaining down of the worlds, in his mind’s eye. This level becomes revealed after he has grasped the entire order of creation (Seder Hishtalshelut) in a way of comprehension, with all of its details, and when they are all focused on one general intent and point. It is then that the essential truth of the heyulie nothingness of the created becomes revealed. Those who have attained these two levels are called, “those who serve G-d with their bodies”.
3) The third level of excitement is the essential arousal and excitement of the Divine soul itself, as it becomes revealed. (This means the whole of the Divine soul, not just a ray from it.) This comes about when he grasps and sees the aspect of the true nothingness itself. In other words, the created “nothingness” becomes completely nullified and sublimated to the Creator, who is the “True Something”. This brings about a limitless arousal and excitement of the soul that ceaselessly rises from level to level (As explained above, that he experiences new insights ceaselessly). Furthermore, since this arousal is essential, his entire being, not just a portion of his soul, becomes aroused towards G-d, who is the “True Something”. This causes his animal soul to also be completely moved and aroused, to the point that he no longer has any connection to matters of this world. He is drawn after G-d with “All his heart”. Those who have attained this level are called “those who serve G-d with their souls”. This level is the ultimate intent of the study of Chassidus, and its entire methodology.