Likutei Moharan 21:1/ליקוטי מוהר"ן כ״א:א׳

1The fourth chapter of Sifra De’ Tzniuta [states]: “Atika Tamir V’satim (Atik is hidden and concealed); Z’er Anpin is revealed and not revealed.” (Zohar II, 178a)

2“When you raise up the candles, [the seven candles shall shine toward the face of the menorah]” (Numbers 8:2). Rashi explains: The flame shall rise up on its own.

3It is written (Psalms 139:5): “Back and front TZaRtani (You formed me).” < TZuRah (form) is the intellect>. <In other words,> there is an intellect which a person attains by means of numerous introductory explanations. This intellect is called “back.” And there is an intellect which comes to a person without any introductory explanation, but through a Godly influx. This is called “front,” the face.

4Now, inspiration of the heart is born out of the motion of the intellect. This is because it is the nature of motion to create heat; the heat created in the heart being commensurate with the swiftness of the intellect’s movements. Thus, due to the Godly influx—i.e. that the intellect is bestowed upon a person swiftly, for he has no need of any introductory explanations—as a result of this swiftness, the flame of the heart rises up continuously on its own.