The last two sections of Parshas Bo are the first two places in the Torah were we find the Mitzvah of Tefillin. At first glance, this seems to be a most peculiar Mitzvah. We are told to place a group of seemingly random Parshiyos from the Torah as a sign on one arm and between our eyes. There are many reasons suggested to explain why the Tefillin go specifically on the arm and head, rather than anywhere else on the body. We put it on the left arm to be near our heart. We put it on our head to be near our brain. But why exactly are we putting these four special Parshiyos anywhere?
A closer look at these four Parshiyos reveals that they appear to symbolize what Judaism is actually all about. Included in these four Parshiyos are many עדות, laws which serve as a testimony to the special relationship between Hashem and the Jewish people, and חוקים, laws which seem to have no rational explanation. These represent two of the three major categories of Jewish Law. Among the עדות are such basic Mitzvos as Ahavas Hashem, Talmud Torah, and Sippur Yetzias Mitzrayim. But there are also laws in these Parshiyos like Arifas Petter Chamor, relating to one's first-born donkey, which seem difficult to understand. These are the types of laws found in our Tefillin.
Interestingly, the types of laws known as Mishpatim are not clearly represented in the Parshiyos of Tefillin. This makes good sense because Mishpatim, which might be called civil laws, are needed even by non-Jewish governments; they are rules for any society. Therefore, they are not pillars of Judaism. עדות and חוקים, though, are unique to Judaism. Our Tefillin thus do not contain random Parshiyos at all; they contain the essence of our religion. It is thus very appropriate that the Mitzvah of Tefillin itself seems to be difficult to comprehend, like a חוק. But the Torah refers to Tefillin as an אות and a זכרון, meaning a special sign. It is thus counted as well among the עדות, with important status.