Reference for Pesachim 124:7
בזמנו שהוא פסול לשום אחרים אחרים פסולין לשמו שלא בזמנו שהוא כשר לשום אחרים אחרים כשרים לשמו
let it retain i own nature:<span class="x" onmousemove="('comment',' Lit., 'it is in its own being'. Hu ('it is') is an emphatic assertion that it must always retain its own peculiar nature, as explained in the text.');"><sup>12</sup></span> neither may it be [slaughtered] in the name of other [sacrifices], nor may others [be slaughtered] in its name; in its time<span class="x" onmousemove="('comment',' Sc. the eve of Passover.');"><sup>13</sup></span> when it is disqualified [if slaughtered] in the name of others, others are disqualified [if slaughtered] in its name; at a different time, when it is fit [if slaughtered] in the name others, others are fit [if slaughtered] in its name.