Tefillin shel Yad Represents “Lo L’shma”
Tefillin shel Rosh Represents the Tikun of L’shma
With this edifying introduction, we will now proceed to explain why HKB”H commanded us to don tefillin shel yad and tefillin shel rosh daily (weekdays). We have learned in the Gemara (Shabbas 63a): "מאי דכתיב אורך ימים בשמאלה עושר וכבוד, אלא בימינה אורך ימים איכא עושר וכבוד ליכא, אלא בימינה למיימינין בה אורך ימים איכא וכל שכן עושר וכבוד, למשמאילים בה עושר וכבוד איכא אורך ימים ליכא." What is the meaning of that which is written (Mishlei 3, 16): “Length of days is in her right hand; in her left hand are wealth and honor”? But can it truly mean that in her right hand there is length of days but there is no wealth or honor?! Rather, the passuk indicates that for those who deal with her right-handedly, there is length of days and, all the more so, wealth and honor; whereas, for those who deal with her left-handedly, there is only wealth and honor but not length of days. In his second explanation, Rashi explains that those who deal with the Torah “righthandedly” refers to those who learn Torah l’shma; whereas those who deal with the Torah “lefthandedly” refers to those who learn Torah not l’shma.
This provides us with some insight as to why we are commanded to don the tefillin shel yad on the left arm first and afterwards to don the tefillin shel rosh. It is because the arms are the implements with which most of the mitzvos are performed. Therefore, the tefillin shel yad on the left arm is donned first to allude to the fact that initially, it is impossible to serve Hashem with Torah and mitzvos l’shma, which is represented by the right. Perforce, we must do so “lo l’shma,” which is represented by the left.
Nevertheless, immediately after donning the shel yad on the left side—alluding to the avodah not l’shma—we don the shel rosh opposite the brain. Thus, we sanctify the thoughts and intellect arising from the brain to fulfill all the mitzvos l’shma. This constitutes a brilliant tikun for all the Torah and mitzvos that were performed “lo l’shma.” For this reason, it is prohibited to interrupt between donning the shel yad and donning the shel rosh. In other words, immediately, when beginning to serve Hashem “lo l’shma,” we are obliged to yearn to do so l’shma. Thus, it turns out that by performing the mitzvah of tefillin as prescribed, it portends the fulfillment of the dictum: "שמתוך שלא לשמה בא לשמה".
This explains magnificently the structure of the tefillin shel rosh. Two straps emerge from its housing; the one that emerges on the right, encircles the right side of the head, while the one that emerges from the left encircles the left side of the head. They come together to form the knot of the tefillin behind the head. This differs from the tefillin shel yad, which is located only on the left side.
Let us explain this structure based on our current discussion. As explained, the purpose of donning the shel rosh immediately after the left-sided shel yad is to rectify the Torah and mitzvos that were performed “lo l’shma”—they were left-sided, so to speak. Therefore, the tefillin shel rosh has a right-sided strap and a left-sided strap to unite the left-sided deed not l’shma with the right-sided intent l’shma. Hence, they unite to form a knot, alluding to the fact that even the left-sided service “lo l’shma” connects with the right-sided service l’shma. Thus, everything ascends and is considered l’shma.
