Reference for Zevachim 14:21
הקישו הכתוב לשלמים מה שלמים בין שינוי קודש בין שינוי בעלים בעינן למצוה אף כל בין שינוי קודש בין שינוי בעלים למצוה
- Rather, said R'Safra: 'And thou shalt sacrifice the Passover-offering' [is required] for R'Nahman's dictum; 'Observe the month of Abib' [is required] for the regulation in respect of changed sanctity; ' Then ye shall say: [It is] the slaughtering of the Lord's Passover' [is required] for the regulation relating to change in respect of owner; 'it is'<span class="x" onmousemove="('comment',' Heb. 'hu', This is regarded as superfluous and hence interpreted as emphasizing the regulation to the extent of making it indispensable.');"><sup>25</sup></span> teaches that it is indispensable, both in the former and in the latter cases.<span class="x" onmousemove="('comment',' A change either in respect of sanctity or owner invalidates the paschal sacrifice.');"><sup>26</sup></span>