Separating from impurity is a crown
Tazria · tumah · separation · nezer · glory of Yisrael
בפסוק והזרתם את בנ"י מטומאתם.
On the verse "and you shall separate Bnei Yisrael from their tumah (impurity)" (Vayikra 15:31).
The Sefas Emes examines the word "v'hizartem," usually rendered "you shall separate/warn," and finds in it a deeper layer of meaning.
הוא ג"כ לשון נזר ועטרה.
It is also an expression of nezer (crown) and atarah (diadem).
The same root letters of "v'hizartem" can also be read as related to "nezer" — a crown. Separating from impurity is thus simultaneously a crowning, an act that adorns Bnei Yisrael with glory.
כי כשזוכין בנ"י לפרוש מן הטומאה בהיותם בעוה"ז תוך הטומאות הוא שבח גדול להם.
For when Bnei Yisrael merit to separate themselves from tumah while they are in this world, surrounded by impurities, it is a great praise for them.
Precisely because Bnei Yisrael live in olam hazeh immersed among forces of impurity, their achievement in holding themselves apart from tumah is especially praiseworthy — a feat that earns them a crown.
לכן כ' ישראל אשר בך אתפאר.
Therefore it is written, "Yisrael, in whom I take glory" (Yeshayahu 49:3).
This is why Hashem declares that He takes pride and glory specifically in Bnei Yisrael — their struggle to stay pure amid impurity is His crowning glory.
הגם כי כמה שרפים עומדים ממעל לו:
Even though many seraphim stand above Him.
Although exalted angels — the seraphim — serve before Hashem on high, He glories not in them but in Bnei Yisrael, for the holiness achieved through struggle in a world of impurity is dearer to Him than the effortless purity of the angels.
Summary: The word "v'hizartem" ("you shall separate from impurity") also bears the sense of "nezer," a crown. When Bnei Yisrael, living in this world amid forces of tumah, succeed in separating themselves from impurity, this very struggle becomes their crown and Hashem's glory — "Yisrael, in whom I take glory" — for He prides Himself in them even above the seraphim who stand before Him, since holiness won through struggle is more precious than the angels' effortless purity.