Mitzvos as garment for hidden holiness

ובמד' ישלח עזרך מקודש כו' מקידוש מעשים וציון מעשים שבידך.

And in the Midrash: "May He send your help from the Sanctuary (mikodesh)" (Tehillim 20:3) — from the sanctification of deeds; "and support you from Tziyon (u'miTziyon)" — from the marking (tziyun) of the deeds in your hand.

The Sefas Emes brings the Midrash that reads "mikodesh" as "from the sanctification of your deeds" and "miTziyon" as "from the distinctive marks (tziyunim) of the deeds you perform" — your help flows from the holiness embedded in your mitzvos.

כי המצות הם רק לבוש ורמז להקדושה הגנוזה בציווי השי"ת.

For the mitzvos are only a garment and a hint to the kedushah (holiness) that is hidden within the command of Hashem.

The physical mitzvah-act is an outer garment clothing a concealed holiness; the true essence is the kedushah hidden inside Hashem's tzivui (commandment).

והם עצות איך להמשיך הקדושה בעוד האדם בלבושו הגשמיי בעוה"ז.

And they are counsel for how to draw down the holiness while a person is still in his physical garment in this world.

Mitzvos function as Divine advice — practical means by which a person, embodied and physical in Olam Hazeh, can channel that hidden kedushah into his life.

ועל ב' הבחי' הללו אומרים קדשנו במצותיו וצונו:

And concerning these two aspects we say, "Who has sanctified us with His mitzvos and commanded us."

The berachah's two phrases correspond to the two dimensions: "kidshanu b'mitzvosav (sanctified us with His mitzvos)" is the hidden kedushah within the act (mikodesh), and "v'tzivanu (and commanded us)" is the outer garment of the tzivui itself (the tziyun/marking of the deed).

Summary: A mitzvah is an outer garment hinting at a hidden kedushah concealed within Hashem's command; mitzvos are the Divine counsel by which an embodied person in this world draws that holiness down into himself. These two dimensions — the inner holiness and the outer commanded act — are expressed in the berachah "kidshanu b'mitzvosav v'tzivanu."