Love of a fellow Jew is not one virtue among others — it is the gate. The Alter Rebbe called it sha'ar ha'aliya, the doorway through which all service ascends, and the three loves (of G-d, of Torah, of Israel) are one indivisible love. It reaches the Jew at the far end of the earth whom you have never seen. The one qualification: draw him upward toward you, never lower yourself to reach him — like oil, which spreads and draws close yet never mixes, and always rises above.
He treats ahavas Yisroel not as a fine trait but as the gate — דא תרעא לאעלאה, the door through which everything else in avodah must pass. Love of G-d, love of Torah and love of a fellow Jew are, in the Alter Rebbe's reading, one and the same. The scope is unconditional: even the Jew at the ends of the earth, even the simplest — "because he is a Jew."
The recurring claims about loving a fellow Jew, by how often each surfaces.
One phrase he turns over three ways: כל ישראל ערבים זה בזה — arevim as sweetness, as intermixture, and as responsibility. Out of ahavas Yisroel all Jews are blended into one and each is answerable for the other.
The rule is total: love reaches the farthest, simplest Jew, without condition. What he qualifies is not whom but how. Drawing a distant Jew close must raise him toward you, never lower you to him — and the love is fixed on the eternal soul, never on the failing, which is bounded and can be erased. Here, verbatim.