To explain in general terms: [The downward flow of Divine illumination is apportioned in either of two ways, which are called] a “measuring-line” (kav hamiddah) and a “measuring-rod” (kneh hamiddah).1 The “measuring-line” gauges and limits [this Divine illumination], thereby making possible the existence of the Ten Sefiros, which consist of “lights” that shine within their respective “vessels”. The “measuring-line” gauges exactly what degree of illumination [or “current”] will match the receptive capacity [or “filament”] of the particular Sefirah into which it will flow, [for the loftier the Sefirah, the greater its absorptive capacity].

The “measuring-line” also delimits the extent to which the Sefiros are drawn forth and expand, just so far and no further. Were it not for this limitation and gauging it would be impossible for the Ten Sefiros to come into being.

This is analogous to the soul-faculties of a person here below: When his will and desire are revealed [i.e., dominant] it is impossible for his intellect to be revealed [i.e., dominant].

With regard to character traits in general, we observe that a person who is capricious by nature will be lacking in intellect, inasmuch as his entire being is wrapped up in his desires. Constantly longing for the objects of his desires, he will not have sated a previous desire yet will already be desiring something else. And so he proceeds from one desire to the next, never finding calm by their fulfillment.

Having one‘s desires satisfied causes pleasure and calms a man‘s spirit. However, this type of individual does not at all seek the resultant pleasure; rather, the longing itself is what is most important to him. We therefore find that such an individual constantly changes the objects of his desires.

[For most people] desire is an outgrowth of pleasure; i.e., they desire pleasurable things that accord with their particular nature. Those who are intellectually inclined derive pleasure from grasping concepts; those who are more emotional by nature derive pleasure from doing someone a good turn or conducting themselves in a goodly fashion. The various levels and kinds [of pleasure depend on the particular composition] of one‘s wisdom, knowledge and understanding [if one is intellectually inclined, or on the balance of one‘s] attributes of kindness and severity [if one is more emotionally inclined]. Each individual‘s longings will thus reflect his natural inclination, one to kindness and one to its opposite [i.e., severity], and so on. Thus, the types of desires [experienced by these people] fall within one of these categories.

This is not so with regard to people whose desires dominate their personalities: their desires fit into no particular pattern [or specific category]. At times they may desire two entirely different (and sometimes opposite) things at the very same instant. It goes without saying that their desires change from one object to another, without limit. This is in line with the saying:2 אין לך דבר שעומד בפני הרצון - “There is nothing that stands in the way of desire,” in the sense that nothing can keep them from fulfilling their desires.

It is true that such intense desire also has great potential merit, for we observe that it can affect all the faculties of the soul, even the intellect. Intellectual attainment is indeed a fundamental [and laudable] trait, especially since mastering the entire length and breadth of a subject demands diligent preparation. Nonetheless we find that the desire to attain knowledge outweighs all else. A person with an intense desire to excel intellectually will inevitably achieve much more meaningful results than another person who is blessed with a keener mind but lacks the burning desire to excel. Hence the advice of our Sages, of blessed memory,3 לעולם ילמוד אדם במקום שלבו חפץ - “A person should always study in a place that his heart desires,” for his desire enhances his comprehension.

[If so, why do we decry those people whose entire lives revolve around their intense desires?]

However, this only applies to the attainment of one‘s desire in an orderly fashion, i.e., where desire plays its role in the harmonious melding and blending of all the soul‘s faculties as they assist one another [in their required tasks. In this context] desire is as crucial as intellect; if a person (Heaven forfend) lacks even one of his soul-faculties he may be considered maimed.

This, however, is not the case with those people whose lives revolve around their desires, and who utilize their other soul-powers only as a means for actualizing their caprices and the like. In such a situation [the faculty of desire] is a detrimental trait.

[Reason and Desire]

[Furthermore, acting in such a manner] defies rationality. Intellect is characterized by quietude and restfulness, as one draws oneself higher and closer to that which is above him, cleaving to a concept in studious contemplation in order to grasp it in all its depth. Chiefly, this entails progressively withdrawing oneself from one‘s own self, and drawing ever closer to the innermost theme of the concept in question. This resembles the state known as “intellectual astonishment and arrestation” (hishtomemus haseichel), wherein the thinker is unaware of the passage of time or of what is happening around him, being completely immersed in his concept.

Desire is the opposite of this state: whenever one desires something he is inevitably conscious only of himself. By its very nature, therefore, desire constrains intellect. When desire is manifest it is impossible to reveal one‘s intellective faculties.

This also explains why when one seeks to satisfy a desire he is liable to commit many acts of folly until he succeeds in satisfying his passion. Everyone knows full well that after having satisfied his desire, he will be astounded by his former actions and will wonder how he could have possibly lost his mind for the sake of such a goal.

For example, while a person is actively pursuing honor, or the like, he is so completely obsessed by this passion that he feels nothing else at all and is drawn to it alone. Moreover, he enslaves all his soul-powers and intellect in his effort to fulfill his wish, doing a multitude of things without rhyme or reason.

Afterwards he will assail himself and wonder at how he was not able to restrain himself and refrain, particularly when he reminds himself of all the details that he experienced along the road to his goal - the falsehood, the chicanery, the deceit, the plotting and projecting as to how he should speak with this person and how he should speak with that, all in order to advance his wiles. [He will be even more astonished upon realizing] that acting in such a manner was contrary to his own basic nature.

All the above results from the fact that when one‘s desire is revealed it is impossible for his intellect to be revealed.

(Elsewhere in the literature of Chassidus it is explained that the plethora of passions causes a man to lose his mind, so that as a matter of course he will commit many foolish acts. We may say that what is written there refers to a different class of people, those who are hedonistic by nature. As our Sages, of blessed memory, say,4 שבנא בעל הנאה - “Shevna was a hedonist,” one of those who seek out the pleasurable potential in everything. Such people are of an even lower caliber than those whose lives are centered around their desires; it is easier for the latter to repent than for outright hedonists.

Possibly the difference between the two corresponds to the difference between those who are “lost” (ohscut) and those who are “banished” )נדחים(.5 Those who are “lost” have acted unwittingly; when they will be “roused by a spirit from above,” and the like, they will surely return. This is not so with regard to the “banished” (Heaven forfend) who have polluted their minds and so forth, and6 “their hearts have been muted” as well. Possibly this is similar to intentional sinning, which is of a yet lower level. At any rate, this matter requires further examination.)

[Intellect and Emotions]

As we have seen, when desire is revealed it is impossible for intellect to be revealed. Hence desire must perforce be limited and circumscribed in its degree of revelation, if room is to be left for intellect to be revealed and drawn forth.

In like manner we can understand how it is Above: Were the Sefirah of Keser [the Sefirah of will and desire] to be revealed to an infinite degree, without limit and measure, it would be impossible for the Sefirah of Chochmah to emanate. So, in turn, must there be a limit and measure in the Sefirah of Chochmah to allow the Sefirah of Binah to emanate. For we observe that when there is a constant outpouring of novel concepts originating in the soul-faculty of Chochmah, it is impossible to arrive at [the] comprehension [and elucidating soul-faculty of Binah]. A limit and measure must therefore be set upon the seminal [concepts of] Chochmah, so as to make possible the emanation of the Sefirah of Binah, thereby bringing an undeveloped seminal concept into the realm of comprehension.

The same is true [with regard to the revelation of intellect and emotions]: while intellect dominates it is impossible for emotions to be freely revealed. We observe this to be so with regard to an intellectual who has thoroughly thought through a concept and is then filled with delight. Even if by nature he is generally somewhat aloof (as is the natural inclination of scholars), at this time he is accessible to all, being friendly even to simple people and to those who are not at all intellectually acute.

Quite the opposite will result when he endeavors to comprehend a subject whose profundity persists in eluding him. In such a case, even if he has the most genial personality, he will nevertheless be ill-tempered and dispirited, dismissing everyone and feeling close to no one.

Both these attitudes result from his high level of intellectual activity, whether in a state of accessibility or in a state of withdrawal. Inevitably, at such a time his emotions will be inactive and uninfluential.

Since neither accessibility nor withdrawal are essential characteristics of the emotions themselves, the emotions can express themselves only when the revelation of intellect is limited. The same is true [with regard to emotions and speech]: when the emotions are in a state of revelation, i.e., when they are given free rein, one cannot speak.

To understand the parallel case with regard to the Sefiros above: In order for the Ten Sefiros to be limited, the lights and their corresponding vessels must be measured. This measurement regulates the degree each Sefirah will be allowed to be drawn downward and expanded. It is through this delineation that each Sefirah makes room for the following Sefirah, and so on.

This, then, is the meaning of the “measuring-line”: it delimits and measures the degree of light to be apportioned to each vessel, and measures the manner in which each Sefirah is to be drawn forth and the point until which it is to expand, thereby making possible the appearance of the next Sefirah, and so on.