Why, indeed, is it easier to immerse the heel in hot water than the head? It is known that the aspect of the soul which clothes itself in the body so as to give it life, possesses two levels of soul powers.1 One level is that of intellect and emotion. The second level is that of delight and will. They are both served by the garments of thought, speech and action, which are also called "attendants to the soul powers."
Intellect and emotion are termed particular and internal soul powers, while delight and will are general and encompassing. The latter are found equally in all parts of the body and therefore do not have specific bodily organs which act as channels or vessels for the powers of delight and will.
The reason for this is as follows: The powers of delight and will are general and encompassing. We observe that "will" affects all parts of the body equally. To the same degree that it affects the lowest bodily power of walking with one's feet, it similarly affects the brain, which is the most important part of the body, containing as it does the highest levels of the particular powers and senses. For this reason, as soon as a person desires to move his foot it will move without the slightest hesitation, since will affects the foot's power of movement.
The above also demonstrates that the power of will is actually found in the foot. Were this not so, there would inevitably be a time-lapse from the moment the will was expressed to its actual fulfillment. Since there is no time-lapse we deduce that the power of will is also found in the foot.
The power of will exerts equal influence upon the foot and the head. When a person is desirous of knowledge the power of will affects his gaining that knowledge. This is in accord with the Talmudic dictum:2 "One should always study where his heart desires, as written3 'For in G-d's Torah is his desire,' " and as Rashi comments, "In those sections that he desires," for one's desire will affect his comprehension.
Summary: Thought, speech and action serve all the soul powers, which are composed of two categories; intellect and emotion which are limited to specific organs of the body, and delight and will which are general powers and affect all parts of the body equally.