Slichos Mystery: What did Yitzchak daven for at the Akeida?

Picture courtesy of The Temple Institute

In slichos this morning for Taanis Esther (and every slichos) we say "mi sheana yitzchak avinu keshene'ekad al gabai hamizbeach, hu ye'a'aneinu!" What does this mean? What did Yitzchak daven for? And in what way was he answered? Did he daven not to be killed? If so then he was indeed answered. But it seems strange with all we hear about him stretching out his neck for slaughter and asking to be bound up not to pasel himself as a korban. Did he daven that he be killed and the fact that it's as if his ashes were burnt on the mizbeach is the way in which he was answered? I'm just not sure what to make of it.

-Dixie Yid

Update: I just asked my rebbe this question. He told me that the Divrei Yoel, by Rav Yoel Teitelbaum of Satmar, gives the following explanation:

As Yitzchak Avinu was about to be slaughtered in order to perform Hashem's will, he was davening that all future generations would have the kochos hanefesh (inner strength) to be moser nefesh if they were called upon as well. And about this, the Payet can say, "He who answered Yitzchak when he was bound on the alter, may he answer us."