Three levels of holiness

והנה ג' קדושות יש ונרמזין במאמר אתה קדוש ושמך קדוש וקדושים כו' יהללוך.

And behold, there are three kedushos (levels of holiness), and they are hinted at in the formula: "You are holy, and Your Name is holy, and holy ones praise You every day" (from the Shemoneh Esrei).

The Sefas Emes finds three distinct levels of kedushah encoded in the bracha of "Atah Kadosh": Hashem Himself, His Name, and the holy ones who praise Him.

כי הקב"ה קדוש ונבדל מכל.

For Hashem is holy and set apart (nivdal) from everything.

The first kedushah is Hashem's own — utterly transcendent and separate from all of creation.

ושמך קדוש הוא התורה שמותיו של הקב"ה שהוא הממוצע שצימצם הקב"ה קדושתו שיוכלו התחתונים לקבל קדושה בכח התורה.

"And Your Name is holy" — this is the Torah, the Names of Hashem, which is the intermediary (memutza) by which Hashem contracted His holiness (tzimtzem) so that the lower beings could receive holiness through the power of the Torah.

The second kedushah is the Torah, which is woven of Hashem's Names; it serves as the bridge whereby Hashem, through tzimtzum, condensed His infinite kedushah into a form the lower worlds can absorb.

וקדושה ג' כפי המקבלים הקדושה ובזה נכללין גם המלאכים שעליהם נאמר וקדושים בכל יום יהללוך.

And the third kedushah is according to those who receive the holiness; and in this are included also the malachim, concerning whom it is said: "and holy ones praise You every day."

The third kedushah is the holiness as it exists in the recipients — including the malachim, the "holy ones" who praise Hashem daily.

ובנ"י יש להם חלק גם בקדושת התורה.

And Bnei Yisrael have a portion also in the holiness of the Torah.

Bnei Yisrael are not limited to the third, "received" kedushah; through the Torah they share in the higher, second level of kedushah as well.

והם ג' קדושות שמתגלין בשבת.

And these are the three kedushos that are revealed on Shabbos.

All three levels of holiness become manifest on Shabbos Kodesh, the day saturated with kedushah.

ועליהם נרמזין הג' סעודות שבת.

And the three Shabbos meals (shalosh seudos) are hinted at in correspondence to them.

The three seudos of Shabbos parallel the three levels of kedushah, each meal drawing down one of them.

תתענג על ה'.

"You shall delight upon Hashem" (Yeshayahu 58:14).

This phrase corresponds to the first kedushah — delighting in Hashem Himself, the highest of the three.

ונחלת יעקב היא התורה.

"And the inheritance of Yaakov" (ibid.) — this is the Torah.

The "inheritance of Yaakov" corresponds to the second kedushah, that of the Torah, the inheritance of Klal Yisrael.

הרכבתיך על במתי ארץ היא קדושה שנמצאת בארץ:

"I will cause you to ride upon the high places of the earth" (ibid.) — this is the holiness that is found in the earth.

This final phrase corresponds to the third kedushah — holiness as it descends and is found within the physical world, "the high places of the earth."

Summary: The bracha of "Atah Kadosh" encodes three levels of kedushah — Hashem who is set apart from all, the Torah (His Names) which bridges down His holiness through tzimtzum, and the holiness as received by the malachim and Bnei Yisrael. All three are revealed on Shabbos and correspond to the three Shabbos seudos and the three phrases of the pasuk in Yeshayahu.