Why does the Torah add the (otherwise superfluous) word "mi'Zovah"?
Refer to 15:13:0.2:1*.
Why does the Torah add the (otherwise superfluous) word Vesafrah Lah"?
When exactly, does a Zavah become Tahor?
Moshav Zekenim citing the Rambam: Whoever the Torah obligates to Tovel is permitted to Tovel during the day, except for a Nidah and Yoledes.
Since the Torah writes "Achar Tit'har" ('after the counting she will become Tahor') and she counts already at the beginning of the seventh day (Rashi, Ibid).
Seeing as we learn Tevilah by a Zavah from the fact that she is comparable ro a Zav, why does the Torah see fit to add "ve'Achar Tit'har"?
Ramban (on Pasuk 11) and Moshav Zekenim (on Pasuk 2): To teach us that she becomes Tahor like other Teme'im who Tovel even in a Mikvah and who do not require Mayim Chayim.
Nidah, 67b #1: To teach us that the seven days must be consecutive, and that consequemtly, in the event that she sees in the middle of the seven clean days, she must begin counting again, and not resume where she left off to merely conclude the seven clean days.
Nidah, 67 #2 (citing R. Shimon): As soon as she has counted the seventh day, she is permitted to Tovel 1 and work in Taharos.
Nidah (Ibid.): Chazal however, forbade her to do so because she may have a sighting before nightfall, which would render her Tamei retroactively and disqualify all the Taharos that she worked on. See Torah Temimah, note 121.
What is the source that a Zavah must Tovel to become Tahor?