Sforno on Genesis 27:33/ספורנו על בראשית כ״ז:ל״ג

1?מי איפוא הוא, if it is indeed true that you are Esau, who was the one who served me venison? When the word איפוא appears with the letter א at the end, the word is an alternative for the two words אם כן, “if so.” When the same word (phonetically speaking) is spelled with the letter ה at the end, as for instance, in Genesis 37,16 איפה הם רועים?, the word means the same as איה, “where?”

2גם ברוך יהיה, the appropriate translation of the whole verse would be: “if this is so that you are indeed Esau, who is the one who brought me the venison and still achieved that he will remain blessed?!” Yitzchok had felt instinctively at the time he had bestowed the blessing that it would become fulfilled for the person whom he was blessing at the time. This confirms something told us by Rabbi Chanina in Berachot 34 that whenever he prayed for the recovery of a sick person he could feel while praying for him if his prayer would be effective.