The first step of ritual slaughtering is preparing the knife. The knife must be perfectly smooth and free of any nicks. The shochet must check the knife by running it gently over his thumbnail before proceeding with the ritual slaughtering.
When you inspect the knife and sharpen it on the stone, your intention should be to remove all its defects [i.e., nicks]. The numerical value of the word for "defect" [in Hebrew, "pagam", spelled pei-gimel-mem] is  equivalent to three times the number of letters in the divine name Eh‑yeh when it is spelled in its simple form and two iterations of its spelling-out.
These [iterations of the name Eh‑yeh] are thus all manifestations of the attribute of judgment; you should intend to sweeten them.
The divine name Eh‑yeh is associated with the sefira of bina. Whereas chochma is the pristine experience of transcendent insight, bina is the analysis of the insight and its integration into the pre-existing mental structures of the mind. The mental process of chochma is an experience of wonder and openness, while that of bina is an experience of evaluation and judgment. Thus, the name Eh‑yeh is associated with judgment. Will it be slaughtered in order to…augment the world's consciousness of G‑d...?
It is instructive to note that the only time this name is used in the Bible is in the exchange between G‑d and Moses at the burning bush. Moses asks G‑d what he should tell the Jewish people G‑d's Name is. G‑d answers: "I shall be who I shall be". Rashi explains that G‑d was telling Moses to reassure the Jewish people that G‑d will be with them in future exiles, just as He was with them in the Egyptian exile. Thus, even the basic meaning of the name Eh‑yeh is associated with exile, a manifestation of the divine attribute of judgment.
The way this is done is by raising the number 41 to the number 42. Forty-two is the number of letters in the divine name Havayah when it is spelled in its simple form and two iterations of its spelling-out.
The divine name Havayah is associated with G‑d's attribute of mercy. There are four standard ways in which this name is spelled-out. If we consider the first three ways of spelling the name, we note that the number of letters in the simple spelling and two iterations of spelling-out together is 42.
[You should count only the number of letters in the spellings-out of] the name Havayah whose numerical value are 72, 63, and 45. Three times 42 [= 126, which] is the numerical value of the word for "defect" ["pagam", 123] plus one for each of the three letters that compose the word itself [pei, gimel, and mem].
These names Havayah indicate divine mercy, which you have now substituted for the attribute of judgment indicated by the 41 letters of the name Eh‑yeh, as we said.
The fourth spelling-out of the name Havayah, whose numerical value is 52 and is spelled out using the letter hei, does not possess 42 letters [in its simple spelling and two iterations of spelling-out].
Therefore, it cannot "counteract" the 41 letters of the spelling out of the name Eh‑yeh and does not figure in this meditation.
Now, when you slaughter the animal, have in mind that the numerical value of the word for "the slaughtering" [in Hebrew, "hashechita", spelled hei-shin-chet-yud-tet-hei] is 337, which is three times the numerical value of the word "Yabok" [spelled yud-beit-kuf, which has a numerical value of 112].
3 x 112 = 336; adding 1 for the value of the word "Yabok"as a whole gives 337. "Yabok" (or "Jabok") is the name of the river next to which Jacob wrestled with the angel of Esau. Slaughtering is thus a specific case of the cosmic struggle between good and evil, divine consciousness and gross material consciousness. Will the animal be slaughtered in order for man to satisfy his craving for meat, to aggrandize his animal nature? Or will it be slaughtered in order to heighten the awareness of G‑d's magnificence in creating the taste and satiation that accompany eating, and by utilizing the energy gained from eating to augment the world's consciousness of G‑d through Torah study and observance of the commandments?
 is also the combined numerical value of the names Havayah  and Elokim . These two names are situated in the throat, which is where the animal is slaughtered.
This will be explained presently. Whereas during the sharpening of the knife, the negativity of the name Eh‑yeh was sweetened by the name Havayah, during the slaughtering itself, the negativity of the name Elokim will be sweetened by the name Havayah.
Have in mind that the numerical value of the word for "throat" [in Hebrew, "garon", spelled gimel-reish-vav-nun, which has a numerical value of 259] is three times that of the name Elokim.
86 x 3 = 258; adding 1 for the value of the name Elokim as a whole gives 259.
These [three names Elokim] are the three immature "brains" which descend there [i.e., to the throat], as part of the development process of Zeir Anpin, as is known.
As we have explained previously, Zeir Anpin passes through three stage of consciousness in the course of its development as a partzuf. These are fetal consciousness, suckling consciousness, and mature consciousness. Mature consciousness is characterized by the mature influence of the intellect over the emotions. In other words, the consciousness of the intellect must, so to speak, descend into the realm of the emotions. The ideas and consciousness of the intellect…contract in order to pass through the neck on the way to the heart…
The conscious powers of the soul are all associated with corresponding locations within the body. Intellect is, of course, "in" the head, while the emotions are "in" the heart or torso. Between the head and the torso is the neck, which is of much smaller diameter than either the head or the torso. Thus, we may envision the ideas and consciousness of the intellect having to contract in order to pass through the neck on the way to the heart, where they can expand again to inform and permeate the emotions.
This contraction is necessary since intellect and emotion are two different worlds, and were the consciousness of the intellect to attempt to influence the emotions without any quantum leap of level (tzimtzum), the emotions would not be able to "relate to" or internalize any of the intellect's level of awareness. This neck-stage is thus crucial for the emotional maturation of Zeir Anpin (and by extension, every human being, who is a projection and manifestation of Zeir Anpin).
So, first, the three brains (chochma, bina, and daat) descend into the neck region on their way to the heart. But, as we said, these are mentalities of constricted consciousness, created by the power of contraction of the name Elokim. This name indicates G‑d's power and strength of restraint. In order for these levels of consciousness to be able to influence the heart properly, they must be influenced here, before descending any further, by the name Havayah, indicating G‑d's mercy.
At this point, these names are manifestations solely of G‑d's judgment. Therefore have in mind to elicit three names Havayah, indicating mature consciousness. [Combining the names Havayah and Elokim thus] will give three times Havayah-Elokim, which as we said, is the numerical value of the word for "the slaughtering". By removing the blood…one allows…mature consciousness to shine into the soul incarnated into the animal…
By removing the blood [which embodies] the attribute of judgment, one allows the three names Havayah that embody mature consciousness to shine into the soul incarnated into the animal. This rectifies it.
Blood is red, the color of severity and judgment (gevura).
After this, meditate on the fact that there are two channels in the throat [i.e., the trachea and the esophagus]. The numerical value of the word [used here to refer to an indicator of kosher slaughter] "sign" [in Hebrew "siman", spelled samech-yud-mem-nun, 160] is the same as that of the name Eh‑yeh when spelled-out with the letter yud.
The numerical value of the first iteration of the spelling out of the name Eh‑yeh using the letter yud is 161. So this equivalence requires adding 1 for the value of the word for "sign" as a whole.
The numerical value of the word for "trachea" [in Hebrew, "kaneh", spelled kuf-nun-hei, 155] is the same as that of the name Eh‑yeh, when spelled out with the letter hei, plus 4 for sweetening each of the four base-letters of this name.
The numerical value of the first iteration of the spelling out of the name Eh‑yeh using the letter hei is 151.
The numerical value of the word for "esophagus" [in Hebrew, "veshet", spelled vav-shin-tet, with a numerical value of 315] is seven times the numerical value of the word for "man" [in Hebrew, "adam", spelled alef-dalet-mem, equaling 45]. This number  is also related to the 320 states of severity associated with the blood of the throat, which is also a manifestation of severity.
We are to picture the mentality of the brain figuratively descending through the two channels of the throat into the torso. The act of ritual slaughtering, which empties these vessels of their blood, neutralizes the negative forces that threaten to thwart the safe passage of divine consciousness from head to heart.
Seven is the number of emotions that compose Zeir Anpin, the archetypal man-figure, as we have noted. It is these seven emotions whose rectification depends upon the successful transference of mind-consciousness through ritual slaughter. Thus, the seven man-emotions are rectified via the esophagus.
The number 320 is derived from the 288 Sparks of divine light that fell from the world of Tohu and became embedded as self-oriented consciousness and egocentricity in the fabric of the lower worlds, including ours. To this number is added the number 32, the number of times the name Elokim (the name signifying divine judgment and severity) appears in the story of creation. The "320 states of severity" thus signify the negativity and egocentricity inherent in creation since the fall accompanying the primordial sin, which our task is to counteract by eliciting divine mercy and love.
The equivalence of 315 and 320 is arrived at probably by adding the definite article ("the", indicated by the Hebrew letter hei, which has a numerical value of 5) to the word for "esophagus" ("ha-veshet").
Now, through ritual slaughter, the dross in these states of severity is sweetened and refined.
Translated and adapted by Moshe-Yaakov Wisnefsky from Shaar HaMitzvot and Taamei HaMitzvot; subsequently published in "Apples From the Orchard." available at Kabbala Online Shop]
Reprinted with permission from Chabad of California. Copyright 2004 by Chabad of California, Inc. All rights reserved, including the right to reproduce this work or portions thereof, in any form, without permission, in writing, from Chabad of California, Inc.