Reference for Bava Batra 187:14
אי הכי
Now, it has been assumed that the quarter [in the case] of <i>kilayim</i><span class="x" onmousemove="('comment',' [H] 'mingled seed'. V. n. 12. ');"><sup>26</sup></span> is [in the same category] as [the quantity of] more than a quarter here,<span class="x" onmousemove="('comment',' In the case of a purchase. ');"><sup>27</sup></span> and yet it has [only] been taught. 'it shall be reduced',<span class="x" onmousemove="('comment',' The entire se'ah is not disqualified by reason of the excess, and as soon as the excess is reduced (from a 'quarter' to 'less than a quarter') the grain may be sown. ');"><sup>28</sup></span> [while the rest may be sown. Why, then, in the case of a purchase,<span class="x" onmousemove="('comment',' In the case of a purchase also, it should suffice to reduce the 'more than a quarter' of the refuse to a 'quarter'. by the seller's paying of compensation for the excess. ');"><sup>29</sup></span> must compensation be paid for all the refuse]? — No; a quarter [in the case] of <i>kilayim</i> is [in] the same [category] as a quarter here.<span class="x" onmousemove="('comment',' In both eases such a small quantity as a quarter of a kab in a se'ah is disregarded. But if this quantity is exceeded, it might, indeed, have to be removed in its entirety even in the case of kilayim. ');"><sup>30</sup></span> If so,<span class="x" onmousemove="('comment',' That a quarter is disregarded, even in the case of kilayim. ');"><sup>31</sup></span> why should it be reduced? — On account of the restrictions of the law of <i>kilayim</i>.<span class="x" onmousemove="('comment',' It is a restriction imposed by the Rabbis to prevent people from transgressing the laws of kilayim. ');"><sup>32</sup></span> If so,<span class="x" onmousemove="('comment',' That the restriction is only Rabbinical, and that in accordance with the Biblical law there is no need to reduce. ');"><sup>33</sup></span>