וְזֹ֛את תִּהְיֶ֥ה טֻמְאָת֖וֹ בְּזוֹב֑וֹ רָ֣ר בְּשָׂר֞וֹ אֶת־זוֹב֗וֹ אֽוֹ־הֶחְתִּ֤ים בְּשָׂרוֹ֙ מִזּוֹב֔וֹ טֻמְאָת֖וֹ הִֽוא׃
И это будет его нечистотой в его проблеме: будет ли его плоть бежать от его проблемы, или его плоть остановлена от его проблемы, это его нечистота.
Rashi
The zav with the number of sightings - because the word zov is written three times in that verse [Leviticus 15:3], followed by "his impurity means this," which implies that it is through these three [sightings] that the zav becomes impure; it also writes "this" which implies that this only applies to what is [specifically] written about [in that verse, namely]: a zav [becomes impure] due to sightings. However, a zava is not [impure for seven days] due to sightings [alone].
Rashi
Deals with sightings - that "and this" [Leviticus 15:3] is written regarding sightings [by a zav] and excludes [impurity for seven days due to] sightings of a zava.
Rashi
His saliva. His saliva; anything which drips is called 'ריר' as in, 'in saliva [בְּרִיר] of health',14Iyov 6:6. and as in, '[whether] his flesh run [דָר]'.15Vayikra 15:3.