All the vessels can be filled only by each other and by bestowing upon one another. To the extent that you bestow on upon others, you bestow upon the Creator. The more you can connect with others, the more you connect with the Creator. This is called: “I dwell within my people” because if you connect with others, you find the Creator there.
Therefore, “Love thy friend as thyself is the great rule of the Torah” since by bestowing upon your friend, you bestow upon the Creator. It is the only thing you should do, and there is nothing more than that. To bestow upon the Creator refers to the general vessel and the general Light that fills it. With regard to others, we perform individual correction that cannot be fulfilled through them if you don’t intend to bring contentment to the Creator, meaning the general vessel.
We cannot perceive the Creator in any other way but through the general force of bestowal that is revealed in the general vessel, in the general desire. If we want to avoid the bestowal upon others within the general network, it prevents us from doing the right thing and it cuts us off from reality since all of reality is based only on the connection among us. There, the general bestowal called the upper Light, the general law called “the Creator,” is revealed.
Therefore it says “Love thy friend as thyself is the great rule of the Torah.”
From the 3rd part of the Daily Kabbalah Lesson 6/07/12, The Study of the Ten Sefirot