It can be said that the concept of Tefilah in a manner of Matnas Chinom corresponds to Shabbos.
External Dimension of Kesser: Therefore, it is included as one of the ten expressions of prayer because the external dimension of ‘Kesser’ is a close encompass and furthermore it pervades the ten Sefiros. Incidentally every prayer is for a new will which is Kesser which understandably is complete when it is in the scope of ‘Bechol Me’odecho’ - without limitations (Kesser).
Who is praying: Because in reality one’s merits do play a role with regards to the prayer itself.
Everything is as nought: In comparison all existence of absolutely no value.
Matnas Chinom: And there is no scope to ask for anything as retribution for merits and good deeds.
Matnas Chinom: This is a very high exalted level of prayer. When a person prays to Hashem whilst in his heart he feels that he does not exist, and he has no merits.
Is a gift: From Hashem to the B’nei Yisroel.
Sages have said: Talmud Shabbos (10b) Rava Bar Mecḥasseya said that Rav Chama bar Gurya said that Rav said: One who gives a gift to another must inform him that he is giving it to him. As it is stated: (Shmos 31:13) “Keep My Shabbosim for it is a sign between Me and you for your generations to know that I am Hashem Who sanctifies you.” When Hakodosh Boruch Hu, gave Shabbos to the B’nei Yisroel, He told Moshe to inform them about it. That was also taught in a Braisa: The Possuk states: “For I am Hashem Who sanctifies you,” meaning that Hakodosh Boruch Hu, said to Moshe: I have a good gift in My treasure house and Shabbos is its name, and I seek to give it to the B’nei Yisroel. Go inform them about it.
Closer perspective: In addition to the fact the Shabbos davening is generally from a feeling of ‘Matnas Chinom’.
State of Shabbos: In contrast to one’s mundane activity in the workday the time of ‘Tefilah’ and the ‘Tefilah’ itself is analogous to a Shabbos in the week.
As it is known: In Chassidus. In Torah Or (Vayakhel 88.1) The Alter Rebbe says: A person in a physical body cannot reach the upper realm of Hashem’s will which is higher than all the worlds in order to draw down the light from there. So first one needs an inspiration from down here to awaken him and elevate him to reach a level of revelation of Hashem's supernal will. This ascent is from the letters of Shabbos which are the same letters from the word that means to return to elevate the worlds from below to above to the highest levels which is Hashem’s supernal will which is revealed on Shabbos at Mincha as the Possuk states וַאֲנִי תְפִלָתִי לְךָ ה' עֵת רָצוֹן “May my prayer to You Hashem be at a propitious time”. The person also has an elevation at this time which is his Neshomoh Yeseira thereafter it is extended into all the days of the week through ‘Tefila’ which is called a ladder and he will then accordingly be able to draw down through his Torah study and his Mitzvos performance a revelation and extension that would not have been available to him had he not had the elevation of Shabbos.
In Likkutei Torah (Behar 41.1) The Alter Rebbe says that it is known that on Shabbos all the worlds have an elevation and all the Torah study and good deeds from all the days of the week are elevated on Shabbos. However, it is not possible for the essence of the weekday to be included in Shabbos however everyday there is a ray of Shabbos as the Possuk says זָכוֹר אֶת יוֹם הַ שַבָת “Remember the day of Shabbos” and that is the ‘Tefilah’ in which all the Torah and good deeds of the whole day are included and elevated. Because ‘Tefilah’ is called ‘Olas Tomid’ - daily burnt offering but the word ‘Olas’ can also mean to elevate referring to the elevation of all the worlds that occurs in prayer. Just as Shabbos which is called ‘Olas Shabbos’ for the elevation that happens on Shabbos. Thereafter all the prayers of all of the days of the week together with all the Torah study and good deeds which are incorporated within them are Mamosh incorporated into the Shabbos.
That is extended: And comes out and is expressed in the days of the week.
