Now, after all of the above explanations regarding the “birth” of Zeir Anpin, (The heartfelt emotions of Atzilut), we may now continue to understand of the various levels of the “maturation” of Zeir Anpin itself, once in is “born”. In the analogy, a physical child is initially born small and then undergoes different stages of maturation until he reaches his most complete state of maturity. Likewise, when the emotions are initially born out of the comprehension, they are brought forth in a completely “immature” state of being, because of the Tzimtzum-lessening between the intellect and the heartfelt emotions (i.e. the “Meitzar HaGaron – the narrow of the neck”). At this point, there is almost a total withdrawal of the intellect, similar to a newborn infant who lacks almost all intellect. Afterwards, however, the emotions slowly develop until, [finally], they reach a complete state of development, in which the light of the intellect radiates to a great degree within the emotions.
This may be understood as follows: When the emotions are in an aspect of a “fetus – Ibbur” within the womb of the “mother – Imma” (Binah), they are only in an aspect of “three within three etc”. That is, the “head” of ChaBa”D (The intellect)is within ChaGa”T (The emotion), and ChaGa”T is within NeHi”Y (The gut emotion). This is like the fetus in its mother’s womb. It is in the fetal position, folded over with its head is between its knees. Likewise, at this stage all that is revealed of the emotions is the aspect of NeHi”Y, which is called the “natural” [or instinctual] (Mootba) aspect of the emotions. That is, the natural character of the child already exists even as it still is in its mother’s womb. This means that a kind and giving person’s nature was already embedded in him at the very start of his inception and while he was being formed in the womb.
Afterwards, when he is born and begins to grow, these natural tendencies and emotions grow with him as well, in accordance to the growth and development of his intellect and reasoning. This is because the intellect and reasoning invests within them in a much more expansive manner than their original capacity, when they were first formed. We can clearly observe that when a person has a personality trait in his youth, this trait is very small and undeveloped compared to how it later develops as his intellect expands and develops.
An example of this is someone who is a spendthrift in his youth. As he grows and his intellect radiates to a greater degree, this characteristic and natural trait will grow and develop to a far greater degree than its original state when he was but a small child. This is because the intellect which vests within the emotion expands it, causing it to grow. As we can see, when a child is born, over time his emotions and characteristics slowly but surely grow, but only in accordance to the growth of his intellect. This is the meaning of the verse, (Proverbs 12:8) “According to his wisdom shall a man be praiseworthy”. This, then, is what is called “Mochin D’Yenika – the Brains of Suckling”, which is the development of the natural character of the emotions (NeHi”Y – Mootba), according to the intellect.
However, this growth is still only an aspect of “Immature Brains” (Mochin D’Katnoot), and is not at all within the category of “Mature Brains” (Mochin D’Gadloot). This is because although the emotions are expanded according to the growth of the intellect, nevertheless, the intellect is invested in them only in a very greatly concealed manner. That is, to the eye, all that can be seen is the natural arousal of the emotions (just as when he was a child). The only difference is that now this character trait has become magnified to a greater degree than when he was an infant. Nevertheless, the intellect is completely and totally concealed. In the above example of a person who by nature is a spendthrift, it is the very same trait, but on a larger scale. Concealed within it, in its innermost depth, is the radiance of the intellect which causes it to grow and spread. Nevertheless, it still exists entirely as an emotional arousal, rather than an intellect one, except that now it is a bigger and greater expression of this same emotional trait.
However, this is not the case in regard to the aspect of the “Mature Brains” (Mochin D’Gadloot) of Zeir Anpin. This is when the emotions actually undergo a profound change of existence and actually exist as intellect. This is brought about by a complete revelation of the intellect and reasoning within the emotions of the heart. Moreover, here, the intellect completely dominates the emotions (rather than vice versa), to the point that there is no felt awareness of the arousal of the natural emotions, whatsoever. Rather, there is a complete arousal and excitement of the intellect only, whereas the arousal of his heartfelt emotions (although this indeed takes place) is totally sublimated to and included in the intellectual arousal. Therefore, it does not exist as something separate and apart from it. This is similar to the matter of the intellectual arousal (explained in Kuntrus HaHitpaalut and in Part Three of ‘The Knowledge of G-d’). We, therefore, find that through the revelation of “Mature Brains”, the state of the heartfelt emotions is actually transformed into intellectual existence. The effect of this is that it actually enhances and expands the intellect itself. At this stage of development, each of the sefirot of the emotions also includes ten complete sefirot.
Furthermore, we find that, in effect, this is the opposite of the aspect of the “Brains of Suckling” (Mochin D’Yenikah), in which the intellect is completely concealed and consumed by the heartfelt emotions and causes them to grow and expand slowly. In contrast, the aspect of “Mature Brains” (Mochin D’Gadlut), is rather, the emotions which are concealed and consumed by the intellect until they themselves take on an existence of intellect and expand it, to the point that the emotions themselves become transformed to exist as intellect. This is the main difference between the aspects of the immature brains of “suckling” (Mochin D’Yenikah) and the mature brains (Mochin D’Gadlut).
From all of the above we may now understand that in Zeir Anpin of Atzilut there also is the aspect of the immature brains (Mochin D’Katnoot) which are called “Brains of Suckling” (Mochin D’Yenikah). This is when the emotional sefirot of Zeir Anpin grow according to the influence they receive from the intellectual sefirot of Abba (Chochmah) and Imma (Binah) of Atzilut, which vests within them in a concealed manner. (This is the aspect of the six mundane days of Creation, as explained in chapter twenty six.)
(As mentioned previously, the aspect of Ibbur – Pregnancy, is actually lower than this, for there is no true consciousness or awareness of reality altogether. Rather, this state of Ibbur – Pregnancy is similar to the state of exile (Galut) which is called “sleep”, as previously explained. During this time the emotions of Atzilut are in their lowest and most immature state of “three within three”, in which only the very lowest level of the natural emotions are revealed (NeHi”Y of NeHi”Y, which is called Mootba – the natural responses (Instinct). In chapter thirty this sleep state is explained at length).
In contrast, there is the aspect of “Mature Brains” (Mochin D’Gadloot) of Zeir Anpin of Atzilut. This is to say that each of the emotional sefirot of Zeir Anpin includes ten sefirot, and the aspect of ChaBa”D (the intellectual aspect – Mooskal) of each emotion comes into revelation and overpowers the felt emotional arousal (Moorgash – ChaGa”T) and the natural character of the emotions (Mootba – NeHi”Y). This causes the emotional sefirot of Zeir Anpin to be transformed into intellect, as explained above. (This is the aspect of the seventh day of Shabbat, as explained in chapter twenty six.) This is when the entire light of Abba (Chochmah) becomes revealed and radiates within the “six directions” of Zeir Anpin, as stated, “What (Ma”H) is his name, and what (Ma”H) is his son’s name”. That is, the aspect of the Koach Ma”H of Chochmah (which is the complete sublimation to the depth of the intellectual subject matter) radiates within the aspect of Zeir Anpin, which is called Ma”H.
 Included here is the explanation of the aspect of intellectual love and fear from part three of ‘The Knowledge of G-d’ (which is directly based on Kuntrus HaHitpa’alut and R’ Hillel Paritchers explanations there):
When one’s heart becomes excited through his Hitbonenut and his emotions are completely aroused, either with great longing, joy or bitterness etc., the entire length and breadth of the G-dly matter which he was contemplating becomes shortened during the actual emotional response. Just an impression of the contemplation remains, as it relates to the excitement and arousal of his emotions only. The length and breadth of the contemplation, recedes and becomes concealed from consciousness. He is only left with what is called a “Tamtzit” (The final essential conclusion), which is the “Therefore” that follows the contemplation.
The recognition of the truth of the “therefore” is what causes the excitement and arousal of his heart. (This is also the explanation of the verse in Genesis, “Therefore a man shall leave his father and his mother etc”. We explained earlier that “father and mother” refers to the Intellectual faculties of Chochmah and Binah. The word “man – Ish” refers to Zeir Anpin, i.e. the emotions of the heart.) An example is one who contemplates how G-d permeates and “fills” all worlds (Memaleh Kol Almin). When his emotions towards G-d become aroused through this contemplation all that remains in his mind is the truth of the “Therefore”, in that he realizes the truth that G-d fills all worlds. Once he is aroused emotionally, the entire contemplation which preceded the “Therefore” recedes from his consciousness and becomes concealed. This level is called Mochin D’Katnut – “Brains of Smallness”.
This means that the intellect (brains) becomes small and its light is concealed. All that remains is the Tamtzit (The final essential conclusion), mentioned above. This level comes about when his contemplation does not reach the depth of the concept. Rather, he only brings the Divine concept closer to the comprehension of his mind by grasping it externally through the allegories and explanations of his teacher. The depth of the concept (The Omek Hamoosag) remains concealed.
(Now, the difference between the Tamtzit and the Omek Hamoosag may be understood as follows: There are two types of essence. The “essence of mint” is not its true essence, but is rather what remains after it has been thoroughly processed until only its essential oil remains. This is the Tamtzit. In the same way, the Tamtzit of a concept isthe “Therefore”, which follows the thorough processing of the concept through Hitbonenut- contemplation. In contrast, the true essence of mint is the source of the mint itself. This is similar to the Omek Hamoosag – the actual depth of the concept. The Omek Hamoosag is the very depth and source of the concept itself. One who grasps the Omek Hamoosag, which is its very essence and source, has a radically different experience, as will now be explained.)
When one’s excitement and arousal is caused by the actual essence of the wisdom, the Omek Hamoosag, which is the very depth and essence of the concept, the very opposite of the above is true. Instead of the intellect receding and becoming “shortened” during the arousal of the emotions, it actually expands due to the emotions of the heart. The arousal of the emotions does not become separated from the intellect, as in the previous level, but on the contrary, it actually strengthens the contemplation and is bound up with the comprehension. This is because the very depths of his mind, heart and soul are completely involved and engrossed in the matter under contemplation.
An example of this is that when a person’s entire heart and mind are completely involved in a personal or business matter or the like, his entire being becomes involved and drawn after it. Because of this deep involvement, since his entire mind, heart and soul are involved, the emotions of the heart are not consciously felt and act as an enhancement to the comprehension, rather than a distraction. This level is called Mochin D’Gadlut – “Brains of Largeness”. In other words, his mental capacities are actually enhanced by the involvement and excitement in the very depth of his heart. (This is in contrast to the external excitement of the emotions of the previous levels. This is an internal excitement and involvement in the very depth of the heart. However, this is not to say that the externality of his heart is not also excited with great arousal. Rather, it is not consciously felt because it is completely absorbed and sublimated to the light of the intellect.) This is the fourth level of Divine service, and is called “Intellectual Love and Fear”.