Now, through fulfilling this idea (of going through four aspects of prayer corresponding to Reuven, Shimon, Levi, and Yehuda) expressed in the beginning of the verse, we will come to fulfill what it says in the next part of the verse: “your hand will be at the back of neck of your enemies.”
“Your enemies” refer to the physical matters of this world, and the needs of the physical body. Even though a person needs them, nonetheless, they need to be treated like “the back of the neck” and not like the “face.” The idea of treating physical needs like his “face” is that the person pursues them with emotion and desire, and treating them like “the back of his neck” means that he pursues them without an inner desire, only out of necessity, like “one who gives something to his enemy by throws it to him over the back of his shoulder, without looking at him,” against his (inner) will, and as though he was forced to do so.
And it is “ַָּׁךְדָּי-your hand” that is “at the back of the neck of your enemies,” do not only read “ַָּׁךְדָּי-your hand” but also read it as “ַָּׁך''יֶדוי-your (double) letter י' (two Yuds)” (see Tikunei Zohar 7b). The verse says (Tehillim 145:16) “ן וצָּר יַח לָּכְל ַעיִּּבְ שַמּוָּךֶדָּי תֶא ַחֵת וּפ-You (Hashem) open ‘ָּךֶדָּי-Your hand’ and satisfy the desire of every living thing.” The Zohar (Tikunei Zohar 7b, quoted in the Hebrew footnotes) explains that the word ‘ָּךֶדָּי-Your hand’ in a deeper sense refers to “ָּך''יֶדּוי-your (double) letter י' (two Yuds),” i.e., the letter י' which, when spelled out in full is יו"ד, and if the numerical value of those letters is added up it equals 20 (י'=10, ו'=6, ד'=4, total=20). Since 20 is double the numerical value of י'=10, so a fully spelled י' is like a double י'.
This “double י'” represents two types of י': One represents Chochma-Wisdom, the highest of the Sefiros, and one represents Malchus-Kingship, the lowest of the Sefiros. These are both like a י' since they both represent bittul, selflessness, like a י' that is the smallest, and “humblest” of letters. The difference between these two types of bittul-selflessness is that Malchus is the basic level of selfless devotion not based on deep understanding. This is like the level represented in Modeh Ani as explained above. The bittul of Chochma is total negation of self, due to seeing the King Himself to the point that there is no room for ego at all, like the Shemona Esrai, as explained above.
The idea of “opening” this “ָּך''יֶדּוי-your (double) letter י' (two Yuds),” is to connect these two levels together, so that from the lower level of bittul one reaches the higher level of bittul. Through this “He satisfies the desire of every living thing,” i.e., there is proper flow of Life-force to the person. The Alter Rebbe applies this concept to our verse. Through connecting these two levels of bittul, so that we have a “double י',” as it were, we will then be able to succeed in overcoming our spiritual enemy. This means that we will be able to look at our physical needs as the “back of the neck,” meaning, not to get caught up passionately about them, so that they will not distract us from being passionate about Hashem.
(The Zohar explains that the connection between these two yuds is the letter ו', which represents Ze’eir Anpin. In our maamar this is understood, since Ze’eir Anpin is the emotional attributes, which are essentially love, fear, and mercy. Meaning, the love and fear of Hashem, Reuven and Shimon, and the merciful revelation of Hashem in Torah study, Levi, is what connects the lower level of Yehuda, the lower yud, with the higher level of Yehuda, the higher letter yud, and enable the person to reach the level of “ָּך''יֶדּוי-your (double) letter י'.”)
This (attainment of the higher level of bittul) is also actually “ַָּׁךְדָּי-Your (Hashem’s) hand,” i.e., a kind gift from Above, since (like we say in the Ne’ila prayer of Yom Kippur) “Your right hand is extended to bring in people to return to You,” which is Hashem’s “right hand” and kindness that extends all the downward until it reaches us and enables us to achieve the higher level of bittul.
The idea of “opening” this “ָּך''יֶדּוי-your (double) letter י' (two Yuds),” is to connect these two levels together, so that from the lower level of bittul one reaches the higher level of bittul. Through this “He satisfies the desire of every living thing,” i.e., there is proper flow of Life-force to the person. The Alter Rebbe applies this concept to our verse. Through connecting these two levels of bittul, so that we have a “double י',” as it were, we will then be able to succeed in overcoming our spiritual enemy. This means that we will be able to look at our physical needs as the “back of the neck,” meaning, not to get caught up passionately about them, so that they will not distract us from being passionate about Hashem.
The word “בִּיטוּל-bittul” is difficult to translate, but can mean submission, selflessness, humility, transparency, or becoming part of something greater than itself, or a mixture of all the above. Its meaning is similar to “הוֹד א ה-gratitude/submission/devotion,” perhaps with less emphasis on the gratitude aspect and more emphasis on the negation of ego aspect. For more on the meaning of “bittul” see Rabbi Tzvi Freeman’s article on the topic on Chabad.org: What Is Bittul?
