Why does the Torah write "Vesarafta es ha'Nosar ba'Eish", and not just "Oso"?
Pesachim, 24a: To teach us that it is only Nosar that needs to be burnt, but not other Isurin that one transgressed, 1
See Torah Temimah, note 25.
Why does the Torah add "Ki Kodesh Hu"?
Pesachim, 24a: To teach us that anything that falls under the category of Kodesh that becomes Pasuk is subject to a Lo Sa'aseh.