What are the connotations of the phrase "Vehisvadu es Chatosam"?
Seifer ha'Chinuch: It is a Mitzvas Asei to confess one's sins and to do Teshuvah on them, at any time, but specifically on Yom Kipur. 1
See Seifer ha'Chinuch, Mitzvah 364. See also Torah Temimah citing the Sifri, which confines the Mitzvah of Teshuvah to before one's death (See also Ba'al ha'Turim).
What is the meaning of "Ashamo be'Rosho"?
Rashi and Rashbam: Ot means 'the principal'.
And what are the implications of "la'asher Asham lo"?