Bnei Yisrael made into vessels for the mitzvos

במדרש מגיד דבריו ליעקב כו' אם אין אדם מל א"י לקבל מצות התורה כו'.

In the Midrash: "He tells His words to Yaakov" (Tehillim 147:19), etc. — if a person is not circumcised, he is unable to receive the mitzvos of the Torah, etc.

The Midrash teaches that a person must first be made into a fitting "vessel" — through milah — before he can receive the Torah's mitzvos.

פי' שבקבלת התורה נעשו בני ישראל כלים להיות מוכן לקבל מצות ה' כדאיתא כי בהר סיני הי' כקדושין ועשה השי"ת אותנו כלים כמ"ש אם שמוע תשמעו בקולי והייתם לי סגולה כמ"ש בפרשה הקודמת מזה.

The explanation is that at the receiving of the Torah, Bnei Yisrael became vessels, prepared to receive the mitzvos of Hashem — as is taught that at Har Sinai it was like kiddushin (betrothal), and Hashem made us into vessels, as it is written: "If you will surely hearken to My voice… you shall be to Me a treasure" (Shemos 19:5), as was discussed in the previous parsha.

Matan Torah was like a betrothal between Hashem and Bnei Yisrael; through it they were transformed into vessels capable of holding and fulfilling His mitzvos, becoming His segulah (treasured possession).

ובס' אוה"ח פי' סגולה שנשתנו נפשות בנ"י שהם מסוגלים לקיום מצות השי"ת ע"ש.

And in the sefer Ohr HaChaim he explains "segulah" — that the souls of Bnei Yisrael were changed so that they are suited (mesugalim) for the fulfillment of the mitzvos of Hashem, see there.

The Ohr HaChaim reads "segulah" as a change in the very neshamos of Bnei Yisrael, making them inherently fit for keeping mitzvos.

וזהו מגיד דבריו הגדה לשון המשכה שנמשכו בנ"י אחר הנהגה העליונה של השי"ת.

And this is "He tells (maggid) His words" — "haggadah" being a term of drawing-forth, that Bnei Yisrael were drawn after the supernal guidance of Hashem.

The word "maggid" connotes "drawing" or "pulling along"; at Sinai Bnei Yisrael were drawn to follow Hashem's higher hanhagah, aligning their nature with His will.

לכן כתיב עתה ואלה המשפטים אשר תשים לפניהם.

Therefore it is written now: "And these are the mishpatim (laws) that you shall place before them" (Shemos 21:1).

Only after they had been made into fitting vessels at Sinai could the Torah now "place before them" the detailed mishpatim.

שכבר הם כלים מוכנים אחר הדיברות כו' חקיו ומשפטיו לישראל.

For they are already prepared vessels, after the Dibros (Ten Commandments)… "His statutes and His ordinances to Yisrael" (Tehillim 147:19).

Having received the Aseres HaDibros, Bnei Yisrael were now ready vessels into whom Hashem could place His chukim and mishpatim.

לכן מסיים הפסוק לא עשה כן לכל גוי.

Therefore the pasuk concludes: "He has not done so for any [other] nation" (Tehillim 147:20).

The verse stresses that this transformation into vessels for the mitzvos was granted to Bnei Yisrael alone, to no other nation.

פי' כמ"ש שלא עשנו כגויי הארצות שנפשותינו משונים מנפשותיהם.

The explanation is, as we say [in the prayer], that He did not make us like the nations of the lands — for our souls are different from theirs.

The very neshamos of Bnei Yisrael were made essentially different from those of the nations, fitted for the mitzvos in a way the nations are not.

וכיון שלא עשה כן לכן משפטים בל ידעום:

And since "He has not done so" [for them], therefore "the ordinances — they do not know them" (Tehillim 147:20).

Because the nations were not given this changed nature, they cannot truly grasp the mishpatim; only Bnei Yisrael, transformed into fitting vessels at Sinai, can receive and know the Torah's laws.

Summary: At Matan Torah, which was like a betrothal, Hashem transformed Bnei Yisrael into "vessels" — changing their very neshamos (the meaning of segulah, per the Ohr HaChaim) so they became inherently fit to receive and fulfill the mitzvos. "Maggid devarav" means they were drawn to follow Hashem's supernal guidance. Only after this preparation through the Aseres HaDibros could the Torah "place before them" the detailed mishpatim. And because Hashem did this for no other nation, whose souls remain unchanged, "the ordinances they do not know" — only Yisrael can truly grasp the Torah's laws.