The Talmud several times refers to the “ashes of Yitzchak” (Berakhot 62b, Ta’anit 16a, Zevachim 62a). This is a difficult reference, as Yitzchak was not cremated for ashes to have been produced. The Brisker Rav (as quoted in Chavatzelet HaSharon al haTorah, Bereishit, p. 294) explained this as drawing upon the events following Akeidat Yitzchak. After Avraham removed Yitzchak from the alter, he sacrificed a ram in his place. As Rashi comments, with every action that Avraham performed on the ram, he proclaimed, “may this be as if my son [was undergoing this]. Thus, the ram received the status of Yitzchak, and all references to the ashes of Yitzchak are actually about the ashes of the ram.