Continuing the example of a child, after the child is born, it goes through a process of maturation, in which its faculties develop. Likewise above, Zeir Anpin too goes through a maturation process, until its faculties, the sefirot of Zeir Anpin, become fully developed.
As mentioned before, each of the ten sefirot contains ten sefirot within it. It is, therefore, understood that ChaBa”D has ChaBa”D, ChaGa”T and NeHi”Y within it. Likewise ChaGa”T has ChaBa”D, ChaGa”T and NeHi”Y within it, and NeHi”Y has ChaBa”D, ChaGa”T and NeHi”Y within it.
The explanation of the maturation process is as follows:
1) When a child is newly born, all that is revealed is NeHi”Y, which is the most external aspect of its being. Actually, at this point only NeHi”Y of NeHi”Y is revealed. A newborn infant only has instinctive behavior and conduct. This is the first stage, immediately at birth. Afterwards, when he receives influence from his mother by suckling her milk, the child grows and matures. This initial maturation during the suckling period is called “Gadlut D’Yenikah (The maturation of suckling). The influence from the mother continues until age 6 when his NeHi”Y become fully developed. This is to say that now, not only are NeHi”Y of NeHi”Y revealed, but ChaGa”T and ChaBa”D of NeHi”Y also become revealed. The child now has intellect and emotions. Nonetheless, they are still totally external and instinctive, somewhat like that of an animal. For example, an animal can come up with all sorts of means and ways to get food. In the same way, a child of this age possesses intellect. However, his intellect is controlled by his instinctive emotions. As stated above, the first maturation takes place between the ages 0 through 6.
2) At age six, the child’s NeHi”Y becomes fully developed. He now has all three categories of ChaBa”D, ChaG”aT and NeHi”Y, but only of NeHi”Y. Beginning from age 6 through 9 a second maturation takes place, in which his ChaGa”T becomes developed. At this point, his intellect is developed to the point where he can distinguish between proper and improper behavior. He does not merely behave instinctively, but rather, can conform his behavior to the intellect. For example, if another child hits him, he can control himself and not hit him back, even though his emotions tell him to do so. Rather, he will deal with the problem differently, by asking a responsible adult to intervene. Nonetheless, even at this point, His intellect only relates to the action level. He is not yet contemplating the, “Purpose of life” or any other intellectual investigations into truth and reality etc. This stage of maturation continues to age 9, at which point his ChaGa”T become fully developed. This includes ChaBa”D, ChaGa”T and NeHi”Y of ChaGa”T. This second level of maturation is called Gadlut Rishon D’Imma (The first maturation from the mother.)
3) At age 9 the next stage of maturation begins. This is the maturation of ChaBa”D. He now has more intellect than what is necessary to guide the emotions alone. His intellect can now be developed so that the intellect can control the emotions. This is to say that now the emotions can be directed by the intellect. This maturation continues until his emotions entirely follow the intellect. In contrast, before age 9, his emotions were not in accordance to intellect at all. However, in this stage though he may act in accordance to his intellect, nonetheless, the emotions themselves have not changed. Rather, he is now capable of overpowering and overturning his emotions and behavior to comply completely with the intellect. This is the third stage in the maturation process, whereupon each sefirah of Zeir Anpin now has ChaBa”D, ChaGa”T and NeHi”Y. However, the ChaBa”D on this level of maturation is only the externality of ChaBa”D.
4) The next stage of maturity comes at age 13. This is the level of a Beinoni. At this point he is in complete control of his very desires and nature. He has not transformed them, but he is in complete control. It is for this reason that according to Torah law, a child may sell movable property at the age of 13.
5) The next stage takes place at age 20. This is the level of a Tzaddik. At this point not only can he overpower and control his desires, but he has actually transformed his very nature. An example of this is what took place during the binding of Yitzchak. The verse states, “Abraham sent his hand, and took the knife etc.” Why did it not simply state, “Abraham took the knife”? The reason is because Abraham had so transformed his nature to be sublimated to G-d’s desire that his hand refused to respond. This is because the binding of Yitzchack was just to test Avraham. G-d never actually intended for Yitzchak to be sacrificed, therefore Avraham had to force his hand to go against its nature. It is for this reason that according to the Torah a 20 year old may sell his father’s real estate. Before this level of maturity, he could sell it irresponsibly, for the wrong reasons. He could handle the proceeds of the sale irresponsibly and regret it later. But at this age, because he is the master over his desires, he may now sell real estate.