Zevachim Daf 8 זבחים דַף 8

The Gemara asks for the source that a חטאת sacrificed שלא לשמה is completely פסול. "ושחט אותה לחטאת" – and he shall slaughter it as a chatas teaches שתהא שחיטה לשם חטאת – that its shechitah should be for the sake of a chatas. "ולקח הכהן מדם החטאת" – the Kohen shall take from the blood of the chatas teaches שתהא קבלה לשם חטאת – that the קבלה should be for the sake of a chatas (and הולכה can be derived from קבלה, as taught on Daf 4a). "וכפר עליו הכהן מחטאתו" – the Kohen shall atone for him from his chatas teaches שתהא כפרה לשם חטאת – that the “atonement,” i.e., the זריקה which effects כפרה, should be for the sake of a chatas. Having derived all cases of שינוי קודש, the Gemara presents the source for שינוי בעלים: the above passuk says the Kohen shall atone "עליו" – for him, implying עליו ולא על חבירו – for him, and not for his friend.

The above derashos taught the requirement to sacrifice a chatas לשמה. The Gemara then asks: לעכב מנלן – from where do we know that improper intentions prevent the korban’s validity? After deriving that זריקה with שינוי בעלים would disqualify a חטאת, the Gemara presents a derashah requiring all עבודות of a חטאת נזיר to be לשמה. It suggests deriving חטאת חלב (i.e., a standard חטאת for a כרת violation) from there, but objects that they cannot be derived from one another, because חטאת נזיר has a stringencyשכן יש עמה דמים אחרים – because it has other bloods (i.e., korbanos) brought with it, and חטאת חלב has the stringency of being brought for כרת. Rava then suggests deriving from a derashah requiring all עבודות of a חטאת מצורע to be לשמה, but the Gemara again objects that they cannot be derived from each other for the same reasons. Additionally, none of these three can be derived from the other two with a צד השוה. Finally, the Gemara answers that the היקש to שלמים teaches that a חטאת must be brought לשמה, both regarding שינוי קודש and שינוי בעלים, like shelamim. The above pesukim then teach that it is מעכב for a chatas. Other types of חטאות are derived from these three with a צד השוה.

A Baraisa teaches that if a pesach is brought בזמנו – in its time (Erev Pesach), it is valid if it is brought לשמו, and disqualified if it is brought שלא לשמו. During the rest of the year, the laws are reversed: it is disqualified if it is brought לשמו (because a pesach cannot be brought then), and valid if it is brought שלא לשמו. Shmuel’s father said this last law is derived from the passuk: ואם מן הצאן קרבנו לזבח שלמים לה' – and if from the flock is his offering for a shelamim sacrifice for Hashem, teaching: דבר הבא מן הצאן יהא לזבח שלמים – something which comes from the flock (a pesach) becomes a shelamim sacrifice. Since a pesach during its time is invalidated if it was shechted שלא לשמו, this passuk must refer to a pesach shechted during the year, teaching that if it is offered שלא לשמו, it is valid as a שלמים. The Gemara asks that perhaps this is only if it was shechted as a שלמים, but not for other korbanos. It eventually answers that the word "לזבח" – for a sacrifice is a ריבויא – inclusive term, to include intent for any korban. The Gemara proceeds to explain that it specifically becomes a שלמים, rather than whatever korban it was shechted for, because of the similarities between pesach and shelamim.