創世記 27:18 註釋：Radak

ויבא אל אביו, into the room where he was lying down. He called to him: אבי, seeing he (Yitzchok) could not see him.

הנני, with a dagesh in both letters נ.

?מי אתה, seeing that he had addressed him simply with the word אבי, he had doubts about whose voice he had heard he had to ask: “who are you?”