Likutei Moharan 93:1/ליקוטי מוהר"ן צ״ג:א׳

1Anyone who conducts his business affairs faithfully thereby fulfills the positive commandment “you shall love [God your Lord]” (Deuteronomy 6:5) .

2This [mitzvah] is the root of all the positive commandments, as it is written in the Tikkunim on the verse “Then prepare a tasty dish for me, the way I love it” (Genesis 27:4)—from the positive commandments (Tikkuney Zohar #21, p.51a, 52a) .

3How does one fulfill the mitzvah “you shall love [God your Lord]”? As is brought in the Talmud concerning the verse “you shall love”—that the Name of Heaven becomes beloved through you. How? When a person has read and studied and attended Torah scholars, and his dealing with people is pleasant and he conducts his business affairs faithfully, what do people say? “Fortunate is the one who taught him Torah…” (Yoma 86a). Thus it is that Heaven’s Name grows to be beloved through him and he fulfills the mitzvah of “you shall love,” which is the root of all the mitzvot.