The Torah recognizes that the Satan and his colleagues have been given access to certain points or areas. To counter these - the Torah enjoins us to place competing forces in the form of Holy objects opposite these spots to subdue any negativity they might emit. These areas of susceptibility to the negative forces include the eyes, heart, heel and the entranceway to the home.
Our parasha counts Tefillin and Mezuzot amongst the holy objects needed to counter the negative forces found in some of these areas. In addition based on the Midrash we also assert and advance that the zealous performance of the "lighter" mitzvot related to the area of the "heel" serve to counter some of the more evasive forces associated with the Satan. We will see through the words of the written and oral tradition how the negative forces associated with these areas are systematically subdued specifically by the placement of the holy objects and fulfilment of these "contra" laws.
