All Jewish souls need each other:^[1]  The general souls of the Jewish people are referred to as a leg and at the same time are also referred to as the children of G-d. The reason for this reference of the Jewish people to a leg is to emphasize the incorporation of all the Jewish souls, as we can see from a parable regarding the body. Although certainly the head is considered the higher and more important limb in comparison to the legs, nonetheless, the legs also contain advantages over the head, as the head cannot go anywhere without the legs and the legs are able to carry the head to anywhere he wishes. It is thus found that the head needs the legs. Also in medicine we find a similar advantage in the legs over the head, as the legs and feet contain certain pressure points and nerve endings that are rooted in the brain and directly affect it. Thus, we find that in the treatment of bloodletting, that releasing blood from the feet helps to heal the head, and likewise there are many other medical treatments done to the feet that help heal the head. From this respect, it is the feet that is considered the head and the head that is considered the feet being that it is dependent on it in this respect. Now, just like we find this interconnection in the physical body and how even lower body parts have advantageous aspects over higher body parts, so too it is spiritually that G-d created all levels intertwined and that even lower levels contain advantageous aspects over higher levels, and hence from a certain perspective the lower level is higher than the higher level.

[1] Torah Or p. 1b lines 16-24