Rebbe Nachman teaches us that we “must l’avod (serve) Hashem with both inclinations, with the evil inclination being subservient to the good inclination” (Likutei Moharan I:62:2). Our Sages teach us, “You shall love Hashem your G-d with all levavekha (you heart) (Deuteronomy 6:5) — with both your inclinations (Berakhot 54a).
Our Sages teach us in Berakhot that we should use the energy generated by the yezter hara (evil inclination) to serve the objectives of the yetzer tov (good inclination).
The Torah uses the word levavekha (you heart), rather than the more more common form libkha. The Sages see the doubling of the vet in leVaVekha as an illusion to our heart’s two inclinations. Hence, they are telling us, “You shall love Hashem your G-d with both inclinations, by making your evil inclination subservient to your good inclination.”
Rebbe Nachman then tells us that a person’s heart should be whole with Hashem. There should be no makhloket (dispute) between one’s two inclinations, so that the heart should not be divided, which is an aspect of “Their heart is chalak (divided)” (Hosea 10:2).
Rashi offers two interpretations for “with all your levavekha” (Sifre, Ve’etchanan 7): namely, 1) with both your inclinations; 2) with your heart not divided against G-d. Rebbe here simply combines the two. With a heart not divided against Hashem, a person will be able to overcome all heretical thoughts.
The prophet Hosea speaks about idol worshiping Jews, whose hearts were divided against Hashem. Rebbe Nachman shows us that this is due to conflict within the heart, between a person’s good inclination and evil inclination. When a person is chalak (divided) between devotion to Hashem and submitting to one’s evil inclination, this makhloket (dispute) gives rise to heretical thoughts that distance the person from Hashem. Therefore, we must strive to serve Hashem with a whole heart.
Based on Likutei Moharan Volume VII, BRI, see notes there