...each in accordance with its own function. Each part or limb of the Partzuf is governed by the “heart” in accordance with the nature and function of the part in question. This is obvious, because this overall law is literally like the heart, which governs all the limbs.
Part 2: Altogether there are 613 parts... To be a Partzuf, the Sefirah must be differentiated into its particular details. But the truth is that the total number of details is 613. This number is integral to the mystery of the Likeness of Man, for the Supreme Mind calculated that this was what was necessary in order to give the world the required character.