We may suggest that this pasuk implies an important truth concerning the manner of serving Hashem. The Tefillin we place on the forehead represent man’s external focus in serving Hashem. This concept is in conformity with the pasuk: And all the people of the earth shall see that Hashem’s Name is called upon you (Devarim 28:10). The Tefillin we place on the arm represent man’s inner struggle in serving Hashem. This concept can be derived from the daily prayer which we recite prior to putting on the Tefillin: That it be opposite the heart to subjugate the desires and thoughts of the heart to His service. One must put on the arm Tefillin prior to the head Tefillin. This teaches us that one must first cleanse and purify his inner-self before attempting to reach out to others. Only one who is himself exemplary in serving Hashem can turn his focus to helping to bring others closer to Hashem.
