Reference for Pesachim 28:4
אמר רבא מתניתין קשיתיה מאי איריא דתני נר שנטמא בטמא מת ניתני שנטמא בשרץ
[We can reply]. For whereas there [in the first clause] it was unclean and is [now] unclean, here it was unfit and is [now] unclean?<span class="x" onmousemove="('comment',' V. p. 62, n. 2. The flesh, even in a third degree, being sacred, was definitely unclean, since there can be a fourth degree. But the oil of terumah was only unfit, without power to contaminate, whereas now by being raised to a second degree it becomes unclean. Thus this statement goes beyond R. Hanina's. - The reference must be to oil of terumah. For though there was also sacred oil, viz. 'the oil used in meal-offerings, and there a third degree is unclean in that it defiles by contact, nevertheless when unclean it cannot be used for lighting but must be burnt, like all other sacrifices which had been, invalidated for any reason, so that by burning it together with the derivative of uncleanness and rendering it thereby second, he does not increase the power of defilement.');"><sup>4</sup></span>