Tzara'as as a closed heart reopened by teshuvah

בפסוק נגע צרעת כו'.

On the verse "the affliction of tzara'as…"

The Sefas Emes opens on the parsha's discussion of the skin-affliction of tzara'as, which he will read not merely as a physical malady but as a sign of a spiritual condition.

בזוה"ק צרעת סגירו כו'.

In the Zohar HaKadosh: "tzara'as" denotes "sgiru" (a closing up, a sealing shut)…

The Zohar reads tzara'as as a "closing" — a shutting down of the heart, so that the affliction reflects an inner blockage rather than only an outer blemish.

ע"פ המד' לעשות לרוח משקל.

This is in line with the Midrash on "to make a weight for the wind/spirit" (Iyov 28:25).

He connects this to the teaching that Hashem apportions the "spirit" by measure — the life-force and wisdom given to each person are carefully weighed out, not unlimited.

כי הקב"ה נתן לאדם רוח חיים וחכמה במדה.

For Hashem gave a person a spirit of life and wisdom in a fixed measure.

Each person receives a set allotment of chiyus (vitality) and chochmah; this is a finite resource that can be spent in one direction or another.

ולכן כפי התפשטות החיות והחכמה בגשמיות נחסר לו בעת הצורך לתורה ומצות ונסגר הלב.

Therefore, to the extent that one's vitality and wisdom spread out into physical matters, he is left lacking when he needs them for Torah and mitzvos, and the heart becomes closed.

Because the supply is fixed, pouring one's energy into gashmiyus (physicality) drains what remains for ruchniyus — and the resulting depletion is the "sgiru," the sealing shut of the heart, the inner reality of tzara'as.

והעצה ע"י תשובה מאהבה כמאמר ובא אל הכהן ע"י השתוקקות לחזור לדביקות עליון עי"ז נפתח הלב:

And the remedy is through teshuvah out of love, as in "and he shall come to the kohen" — through yearning to return to the supernal deveykus (attachment to Hashem), by this means the heart is reopened.

The cure for the closed heart is teshuvah me'ahavah (repentance from love): the metzora's coming to the kohen represents a soul rekindling its longing for closeness to Hashem, and that very yearning breaks the seal and opens the heart once more.

Summary: Reading the Zohar's gloss that tzara'as means "a closing," the Sefas Emes explains that each person has a measured supply of vitality and wisdom; squandering it on the physical leaves the heart drained and "sealed shut" for Torah and mitzvos. The remedy is teshuvah me'ahavah — a renewed yearning for deveykus that reopens the closed heart.