(When a Jew wears tefillin, his head, heart, and the limbs of his body stay healthy. If he doesn’t don tefillin, G-d forbid, his head, heart, and all the limbs of his body can become ill to the point where he can fall and become a primary source of uncleanliness [spiritual death].
The point is, everyone can make baalei tshuva if only they do it with mesiras nefesh, in a Chassidic and sincere way.
“Sincere,” as the sages say, “Words from the heart, penetrate the heart [of the listener] and accomplish their intent.”
In a “Chassidic way” means to forgo one’s own needs to do good to another. As is known a Chassid burns his nails to ensure no one is injured by them even though it might endanger the Chassid.
Our Rebbe asks, “What is the connection between tefillin and making a baal tshuva?” An encapsulated version of his answer is that when a person becomes aware of his good fortune and responsibility to serve Hashem (either due to another Jew or his own inner voice), he immediately rationalizes that this path is not for him. The reason is because the desires of his heart overwhelm his intelligence. As our sages teach, a person does not sin unless a spirit of folly enters him.
Therefore, the first step in helping the person do tshuva is having him don tefillin. The arm tefillin is placed across from the heart, where temptation resides. It binds the arm (representing action) to the heart with a band of holiness. Similarly, the head tefillin encompasses his intellect with a band of holiness allowing its true voice to be heeded.
Now when this Jew returns, Hashem reveals His love even more than to a completely righteous person. As it says, “In the place where a baal tshuva stands, a complete tzadik can’t stand.”
Furthermore, the King recognizes his responsibility to thank the one who returned His son, and gives him anything he requests from His full, opened, wide, and holy hand.” [Sicha Yud Tes 5728]
