Kommentar zu Wajikra 15:13

וכי יטהר means WHEN HE CEASETH [FROM HIS ISSUE] (Sifra, Metzora Parashat Zavim, Chapter 5 1).

When he stops. That is, the purity [cessation] of blood [i.e. discharge] and not the purity [cessation] of his impurity, for it is written afterwards: “and bathe in running water and he will be purified.”

לטהרתו, “after his process of purification has begun when the emission has stopped and seven days had elapsed.

שבעת ימים לטהרתו [THEN SHALL HE NUMBER TO HIMSELF] SEVEN DAYS FROM THE DATE WHEN HE CEASED — i. e. seven days clean (free) from the uncleanness resulting from the issue, i. e. in which he sees no issue, and all of them (of the seven days) must be consecutive (Sifra, Metzora Parashat Zavim, Chapter 5 6).

That he not see. Meaning: These seven days have to be pure from the impurity of discharge, otherwise, why does it say, “When a zov will become ritually clean... he shall count for himself...” which implies if it does not stop he does not count? If these days will not be pure from discharge, he has not stopped! Rashi continues to explain: “And all of them consecutive,” as it is written, “for his purification” — that his purification shall be as one. Meaning, he did not see a discharge in the middle, and if he saw in the middle, it disrupts the first days and he must begin to count another seven clean days.

ורחץ בשרו במים חיים, “and he shall bathe his flesh in running water, [emanating from the earth, i.e. a spring; Ed.] The person suffering from such involuntary seminal emissions cannot merely immerse himself in a ritual bath, but requires “living water,” as opposed to stagnant water, such as a collection of rain water. On the other hand, his vessels, as well as a person suffering from the skin disease tzoraat, do not require spring water for their purification.