Why does the Torah insert "v'Chiper" in the previous Pasuk with regard to the Asham, and repeat it here regarding the Chatas, and again in the following Pasuk regarding the Olah and the Minchah?
Ramban (18): The Asham atones for the sin that brought on the Tzara'as, 1 the Chatas for his probably having questioned Hakadosh-Baruch-Hu for punishing him; whereas the Olah and Minchah purify him from his sin and allow him to return to his wife. 2
Hadar Zekenim (15), Moshav Zekenim (53): V'Chiper [regarding Nega'im and Yoledes] is an expression of cleansing. The Tzara'as already atoned for his Aveirah, and Korban Yoledes is not for sin.