Shabbos as the root of all blessing

והנה איתא בזוה"ק דכל ברכאין בשביעאה תליין והוא שורש הברכה.

And behold, it is taught in the Zohar HaKadosh that all blessings depend on the seventh (kol birchan bi'shvi'a talyan), and it is the root of blessing.

The Zohar teaches that every blessing is suspended from the "seventh" — Shabbos. Shabbos is the source from which all brachah flows into the world.

ובנ"י ובשבת ובבהמ"ק בכח אלה הג' הוציאו מכח אל הפועל שורש הברכה בי"ב לחם הפנים למשוך הברכה מן השורש.

And Bnei Yisrael, and Shabbos, and the Beis Hamikdash — through the power of these three, the root of blessing was brought from potential into actuality, in the twelve loaves of the Lechem HaPanim (the Showbread), to draw the blessing from the Root.

Three holy "channels" — Bnei Yisrael, Shabbos, and the Beis Hamikdash — together actualized this hidden root of blessing. The twelve loaves of the Lechem HaPanim, arranged in the Mikdash and renewed each Shabbos, were the vessel through which blessing was drawn down from its Source to the twelve tribes.

וכמ"ש לכו לחמו בלחמי להתדבק בשורש הלחם שהוא התורה.

And as it is written, "Come, eat of My bread (lechu lachamu b'lachmi)" (Mishlei 9:5) — to cleave to the root of the bread, which is the Torah.

The invitation "come, eat of My bread" is a call to cling to the true source of all sustenance — the Torah, which is the spiritual "bread" behind the physical bread.

ולכן מבקשין בש"ק יגלה לן טעמי דבתריסר נהמי שהיא טעם השורש של הברכות.

Therefore on Shabbos Kodesh we request, "may He reveal to us the taste of (the secrets within) the twelve loaves (ta'amei di'vi'sresar nahamei)" — which is the taste of the root of the blessings.

In the Shabbos zemiros (Askinu Seudasa) we ask Hashem to reveal to us the inner "taste" hidden in the twelve loaves — meaning the deepest taste of the very root of all blessing, accessible especially on Shabbos.

ובאמת א"י להרגיש זה הטעם עד שמתקדשין ומתפרשין מטעם עוה"ז הגשמי.

And in truth one cannot sense this "taste" until one becomes sanctified and separates oneself from the taste of this physical world (ta'am olam hazeh ha'gashmi).

This inner taste of the root of blessing remains hidden as long as a person is immersed in the "taste" of physical, material pleasures. Only by sanctifying oneself and separating from gashmiyus can one begin to perceive it.

ושבת הוא מעין עוה"ב:

And Shabbos is a foretaste of olam haba (me'ein olam haba).

Shabbos itself provides this separation: it is a taste of the World to Come, lifting a person above the gashmiyus of olam hazeh so he can sense the hidden taste of the root of all blessing.

Summary: All blessing is rooted in the "seventh" — Shabbos. Through Bnei Yisrael, Shabbos, and the Beis Hamikdash, this root of blessing was actualized in the twelve loaves of the Lechem HaPanim, whose inner "taste" — the source of all brachah, and ultimately the Torah — we ask to perceive on Shabbos. But this taste can only be sensed once one sanctifies himself and separates from the physical pleasures of this world, which is precisely what Shabbos, a foretaste of olam haba, enables.