Chapter eighteen of the Tanya reveals the deepest source of every Jew's connection to God: an inherited love that predates individual experience.
The Tanya has just argued that even a person with limited understanding and no mystical aptitude can serve God fully. But how? The answer: the ahavah mesuteret (אהבה מסותרת), the hidden love, is not something each person must generate on their own. It is a spiritual inheritance from the Patriarchs—Abraham, Isaac, and Jacob.
The Patriarchs were the "chariot" of God. Rabbi Schneur Zalman explains: just as a chariot has no will of its own and is entirely subordinate to its rider, the Patriarchs were so perfectly nullified before God's will that their every thought, word, and deed was a direct expression of the divine. This level of total surrender to God became embedded in the spiritual DNA of their descendants—the nefesh (the vital soul), ruach, and neshamah (the higher soul) of every Jewish soul.
Even the most disconnected Jew carries this inheritance. The Tanya says that even the "most worthless of the worthless" receives, at the moment of conception, at minimum a nefesh d'nefesh of malchut d'Asiyah—the lowest possible grade of holiness in the lowest of the four spiritual worlds. But because the sefirot (the divine emanations) are interconnected, even this lowest grade contains within it a spark of chochmah d'Atzilut—the highest wisdom of the highest world—which is itself illuminated by the light of the Ein Sof (אין סוף), the Infinite.
The implication is staggering. No matter how far a Jew has fallen, no matter how thick the layers of concealment, the light of the Infinite is inside them. Not metaphorically. Not potentially. Actually. Right now. The hidden love is the Infinite's own light, buried so deep that the person carrying it may never feel it consciously. But it is there, and it is indestructible, because it comes not from personal merit but from the covenant with the Patriarchs.