Dvar Torah Bo 5785 - making the weak strong.

At the end of the parsha, as the Jews are leaving Egypt, G-d introduces the mitzvah of tefillin: “It shall be a sign upon your arm (ידכה) and an ornament between your eyes, for with a strong hand Hashem removed us from Egypt.” (Shemos 13:16). On which hand should the tefillin be placed? One might think that the tefillin should always be placed on the left arm, because that would make the tefillin opposite the heart. However, the Talmud (Menachos 37a) learns that because the Torah uses the term ידכה for the arm with the letter “heh” (ה) at the end, we put tefillin on the weaker arm. Rashi explains how the the letter “heh” indicates that tefillin goes on the weaker arm. The final "heh" makes the word feminine, which is the weaker gender, or alternatively it comes from the word כהה, which means weak.

We learn from here that everyone, including those that are left-handed, must put tefillin on the weaker arm. Therefore, a right-handed person places tefillin on his left arm, and a left-handed person places tefillin on his right arm. This is true even though the right arm is not opposite the heart. Why does the Torah mandate that everyone must use the weaker arm for tefillin? In most mitzvos, we use the right arm or the stronger arm for the mitzvah. For example, the lulav is always held in the right hand, the kiddush cup should be held in the right hand, and the Kohen uses the right hand to perform the avodah (the Temple service of the kohanim). Why with tefillin does the Torah command us to use the weaker arm?

Rav Moshe Feinstein ZTL explains that this mitzvah teaches us an important message. When one is in a weaker spiritual situation in life, e.g. one feels that the mitzvos are burdensome or Torah learning is too hard, or life in general is wearing one down, one should not give up or despair. This is a common and perhaps natural situation that many people go through. However, the tefillin on the weaker arm teaches us that through effort, even though it might be hard, one can transform the weak into the strong.

In the physical world, working out in the gym can strengthen one’s weak muscles and build stamina. Likewise, in the spiritual world, instead of giving up or feeling resigned to being weak, the tefillin can inspire us. When learning Torah seems difficult, one can work hard and gradually build up one’s understanding of Torah. When we struggle to improve our middos (character traits), we can slowly progress to becoming better people and more in control of our actions. Because the tefillin are always wrapped on the weaker arm, we see that our weaknesses can become strengths.

Therefore, whatever seems weak today can, with sufficient effort, become strong in the future. As Rav Moshe says, with this merit, our weaker arms will become strong, and then Hashem will bestow upon us all the good things which stem from the right which is strong. As it says in Tehillim (16:11): "In Your presence is perfect joy; delights are ever in Your right hand.”