“And these words that I (Hashem’s Essence) command/connect to you,” must be fulfilled specifically through the physical action of the Mitzvos, as explained above. Moreover, they must be performed “today,” since today refers to the time when the soul is invested in a body. Only while it is invested in a physical body can the soul fulfill the Mitzvos.
Which is not the case before the soul became invested in the body. Then, it only “enjoyed the revelation of the Light of Hashem’s Presence,” i.e., it enjoyed the Light of Hashem’s Wisdom that flows into Gan Eden.
This is the meaning of the continuation of the passage, which states, “And you should teach them (the words of Torah) to your children, and you should speak of them.” This is the Mitzvah of speaking the words of the Torah, as it is written, (Yehoshua 1:8) “And you should speak of them (the words of Torah) by day and by night.”
Lessons in Torah Or
Saying the words of the Torah is considered the physical performance of a mitzvah, since “the movement of a person’s lips when speaking is considered a physical action.” (Bava Metzia 90b)
The idea here is that just like putting on tefillin is a physical mitzvah that connects the person to Hashem’s Unknowable Essence, so too, with regard to physically saying the words of the Torah, the action of moving the lips is a mitzvah that connects the person to Hashem’s Essence. This is in contrast to contemplation of the words of the Torah, which is a purely spiritual activity. Therefore, contemplation is similar to the soul’s connection to Hashem via understanding, which occurs in Gan Eden, rather than to the connection achieved through action mitzvos, including the physical act of verbalizing the words of Torah during study.
This explains why the first verse of Krias Shema begins with contemplating Hashem’s Names, i.e., the levels of Hashem’s Light that permeate and encompass the world.
By thinking about how that Light of Hashem is so great that it creates the whole world and is, moreover, beyond all worlds, a person comes to a yearning for Hashem Himself. If His Light is so great, He Himself is above and beyond anything that has to do with the world. He is the Ultimate True Existence, which has no beginning, end, or limit, in any way. Therefore, a person can consider how there can be nothing in life that is more desirable than to connect Hashem Himself.
This yearning for Hashem’s Essence is called the love of Hashem “בְּכָל מְאֹדֶךָ—with all of one’s might.”
Now that we yearn for Hashem Himself, how do we connect His Essence? To answer this, the verse continues by explaining that when we perform action mitzvos (including verbalizing the words of the Torah), we connect to Hashem’s Essence and fulfill our yearning for Him.
After the Alter Rebbe explained the verse in Shir HaShirim (8:7), that many waters cannot extinguish the love of the soul for Hashem etc., he continues to explain the next verse, 8:8.
The verse reads in full: “אָחוֹת לָנוּ קְטַנָּה וְשָׁדַיִם אֵין לָהּ מַה נַּעֲשֶׂה לַאֲחוֹתֵנוּ בַּיּוֹם שֶׁיְדֻבַּר בָּהּ”—We have a young sister, and she is not ready to get married yet, what should we do for our sister when they speak about her [getting married]?”
