Soul unity
The Torah’s most central commandment, mentioned in this week’s parsha, is to “love your fellow as yourself.” This commandment (said to a prospective convert, phrased in the negative as “what is hateful to you do not do to others”) has been identified by the Sage Hillel as comprising the entire Torah, while the rest is only commentary.
Similarly, the Sage Rabbi Akiva stated that the command to love your fellow as yourself is “a major principle of Torah.” He meant that by observing this command we will be inspired and empowered to observe all the others.
Rabbi Schneur Zalam of Liadi (the founder of the Chabad Chassidic movement, who is also known as the Alter Rebbe) wrote in his classic work, the Tanya, that loving your fellow is connected to all the Commandments, not simply the social Mitzvos. Obviously, one who loves another will not steal from or harm the other. This command goes a step further; even the Mitzvos that involve our relationship with G‑d are connected to loving your fellow as yourself.
The rationale for this statement, the Alter Rebbe explains, is that the only way our love for the other can be just as the love of self, is when our principal identification is with our soul and not with our body. What separates people is the body and its preoccupation with physical interests. In contrast, our souls unite us because they share a common Divine source. By observing the command to love our fellow, by focusing our attention on our souls and allowing them to dominate our lives, we realize the goal of all the commandants: to bring about the dominance of the soul over the body.
Where Did We Meet?
The Ba’al Shem Tov, founder of the Chassidic movement, once commented that this commandment to love our fellow as ourselves applies even to a Jew we have never met.
The love for that Jew is based on the common soul-bond that exists with all Jews, even those we’ve never met.
However, an important question can be raised.  Why would anyone think that our love for the other, deriving as it does from the realization that our souls are connected, would be diminished just because we’d never met?  
If the Ba’al Shem Tov had said that we should love even a person with whom we have nothing in common, because of his or her compromised spiritual status, that would have made sense. We might well have thought that one whose soul is suppressed cannot be loved as much as one whose soul radiates holiness. But why should the fact that we never met this person affect our love for him or her?
The answer, based on a talk of the Rebbe, is that the Ba’al Shem Tov was not referring to one whom we have not met physically but one whom we have not met spiritually. We must love even those Jews who have strayed far from Judaism as they too possess a Divine soul that fuses all of the Jewish people into one harmonious entity.
This explanation thus reinterprets the Ba’al Shem Tov’s reference to a Jew whom we never met as a metaphor for one whose level of observance differs from our own.
A Jew Who Never Prayed
In yet another talk, the Rebbe addressed the idea of the Jew whom we have not met in a novel and fascinating way. The Rebbe posits that there can almost never be a situation in which two Jews have not met. This, the Rebbe bases on the fact that when a Jew prays, his or her prayers are directed towards Jerusalem, and more specifically, towards the Bais Hamikdash, the holy Temple. That is where all of our prayers coalesce into one unified force and go up to G‑d.
Moreover, the Ba’al Shem Tov taught that a person exists where his will is. If our will is to be in the Holy Temple, that is where we truly reside, without regard to where our bodies are situated. When do we express our innermost desires? When we address G‑d in prayer and request our needs from Him. Prayer expresses the deepest feelings and will of the person who prays.
Thus, every time we pray, when our most heartfelt thoughts and expressions of our will are directed towards the Bais Hamikdash, that is where we truly reside. Not only are all of our prayers concentrated in the Bais Hamikdash, even our own personalities, channeled through our prayers, are situated in the Bais Hamikdash.
Thus, the Rebbe concluded, when a Jew has prayed, he or she has inevitably met other Jews in the Temple who are likewise present through prayer. Thus, the only way we can refer to a Jew that we never met is to speak of a Jew who has never once prayed in his or her life. This describes a Jew who has never expressed even a hint of anguish to G‑d for his or her pain even if not through formal prayer. The expression, “O, my G‑d,” said with a modicum of feeling, transports that Jewish soul to the Bais Hamikdash and where it meets face to face with every other Jewish soul that has vented to G‑d.
The Ba’al Shem Tov’s message is that those Jews too must be loved. Even though that Jewish soul is in exile and cannot express itself as it wants, we are still connected to it. That Jew’s soul-in-exile wants to be in the Bais Hamikdash, although he or she may not be able to overtly express it.  That Jew must be loved no less than the Jew who we always meet in the Bais Hamikdash.
Senseless Love
Our Sages teach that the Bais Hamikdash, the place that united Jews for centuries, was destroyed because of our communal disunity; because of senseless hatred, to be more precise. The Rebbe always emphasized that the Third Temple will be rebuilt and the ensuing Era of Redemption enabled through “senseless” or supra-rational love. Random hatred is countered by random acts of kindness.
What is the difference between senseless love and just plain love?
When we have a good reason to love someone it is through a measured, limited and temporal form of love. It makes sense to reciprocate love with someone who has shown you their love or who possesses certain qualities that make him or her endearing.
When there is no rhyme or reason for the love, and we persist loving that person, that love is said to transcend logic and reason.
One manifestation of measured love is when the other earns our love because of that individual’s exemplary behavior, particularly when we benefit from that person’s goodness.
When, however, we are so far apart from the Jew that we have never met, on any level, when our prayers have not converged in the Bais Hamikdash, and we can still love that person, that is what we mean by senseless, trans-rational love.
Even when we have good reason to love someone, we must learn to transcend that reason.  We must recognize that all of the Jewish people form one unified body and, we are all essential parts of one indivisible essence.