פירוש על בראשית 27:30

יצא יצא [JACOB] WAS YET SCARCE GONE OUT — this means, as one went out the other came in (Midrash Tanchuma, Toldot 11).

ויהי אך יצא יצא, this detail has been recorded to illustrate the miracles which were performed in order to enable Yaakov to obtain this blessing. If Esau had returned just one minute sooner, Yaakov would not have secured this blessing.

ויהי כאשר כלה, As soon as he had finished, etc. The reason for the apparently superfluous word ויהי which always introduces something of a painful nature, is that the Torah testifies that Isaac completed his blessing prematurely; instead of giving Jacob the entire blessing he was capable of bestowing as he did for Esau afterwards, he did not do so now. Had Isaac truly completed giving Jacob all the blessings he was capable of bestowing, Esau would have gone out empty-handed.