Hillel meant it quite literally –– love for our fellow really is the entirety of the Torah. Let’s examine the two-fold spiritual dynamic of the Torah. One aspect is about transcending the body and identifying with the soul. And another aspect is about drawing down the infinite light of the Divine, bringing it to be manifestly expressed within the world. Looking at the mitzvah of love, we can see that these two dynamics are most perfectly expressed right here in this mitzvah. In order to truly love another, we need to transcend our ego and identify with the soul. And –– by actually loving another, bonding through love, we draw down the infinite light of the Divine into all of the worlds. This is the entire Torah.