What is this Pasuk, which is seemingly superfluous, coming to teach us?
Nidah, 63a: It comes to teach us the Din of Heset. 1
Kidushin, 25a: It teaches us that, whatever is touchable
What does the Torah mean when it writes "ve'Yadav Lo Shataf ba'Mayim"?
Rashi (citing Chulin, 106a): It means that as long as the Zav has not Toveled his whole body, he remains Tamei 1 (even after many years
Even after his Zivus has terminated and he has counted seven clean days (Rashi).
Like we find in Mishlei, 30:20 and in Shoftim, 3:24 (Rashbam).
As implied by the word "Shataf" (See for example, Vayikra 6:21 and Yeshayah, 28:2 (Rashbam).
Seeing as "ve'Yadav Lo Shataf" refers to his whole body, why does the Torah mention hands?
Rashi (citing the Sifra and Zavim, 4:5): To teach us that it is only open parts of the body, such as the hands, that must actually have contact with the water, but not parts of the body that are hidden (such as underneath the arm-pits).
Ramban: Refer to 15:11:1:2.
Chulin, 106a: This is a support (Asmachta) for the Mitzvah de'Rabbanan to wash the hands.
QUESTIONS ON RASHI
Rashi writes that "Shataf" refers to Tevilah. Why did the Torah call it 'Shetifah' (rinsing)?
Ramban and Moshav Zekenim: This teaches that the Rechitzah (Tevilah) includes rinsing and scrubbing to remove any Chatzitzah.
