The necessary intentions when donning tefillin
When discussing tefillin the Torah says: "...in order that Hashem's Torah may be in your mouth, for with a strong hand Hashem removed you from Mitzrayim." Chazal understood the pasuk to be instructing us to bear in mind a special kavanah for tefillin on top of the standard kavanah needed for every mitzva. When putting on tefillin one should consider that these four parshiyos -- shema, v'haya im shamoa, kadesh and v'haya ki yeviacha - declare: 1) the Oneness of Hashem, 2) yetzias Mitzrayim and the many miracles that Hashem performs for us, and 3) Hashem's ability to control His creations. We are to tie the tefillin on our arms (near our hearts) and on our heads (the seat of the neshama) as a reminder of the obligation to serve Him with our hearts and minds.
(סעיף ה וס"ק טו)