This then is the meaning of the passuk: “So now, write this song for yourselves.” It is referring to Torah she’b’chsav, where writing it transforms the “skin” of the animal into a Torah of “light.” But that is not enough! The goal is to “teach it to Bnei Yisrael and place it in their mouth.” By having them place Torah she’b’al peh in their mouths, the mouth becomes a vessel ready to be the parchment of Torah she’b’al peh. In this manner, a person’s own “garment of skin” is rectified and becomes a “garment of light” once more.
Now, this enlightens us as to why it is a mitzvah for everyone in attendance to carefully gaze upon the letters of the sefer-Torah when it is held up high. Thus, they will realize that if the “skin” of an animal can be elevated to a Torah of “light” via the letters of the Torah, all the more so that they can elevate their bodies from garments of “skin” to garments of “light.”
This also explains very nicely the claim of the Arizal: “By gazing upon the letters from up close so that he can read them easily, a person is imbued with a potent light.” For, when a person gazes upon the letters in a sefer-Torah that transformed and elevated the “skin” of an animal to the kedushah of a Torah of “light,” they have a tremendous impact on him. They enable him to elevate his animal self from a “garment of skin” to a “garment of light.”
