In Parshat Toldot, Yaakov followed his mother Rivka's advice and dressed up like his brother Esav. The reason why Yaakov went to all of this trouble was to ensure that he would receive the first and best blessing.

In reality, the true blessing was not the first blessing which was given when Yitzchak was being deceived. The true blessing was in fact the third blessing which Yitzchak gave to Yaakov knowing full well who he was blessing. The third blessing is found in Breisheet 28: 3-4: "May God bless you, make you fruitful and multiply you. May you become an assembly of peoples. May He give you the blessing of Avraham, to you and your descendants with you that you may inherit the land of your dwelling that God gave to Avraham".

According to Rashi, the blessing of Avraham refers to the brachot of "I will make you a great nation" and "Through your children all of the nations of the world will be blessed".

Radak points out that Yitzchak was making it clear to Yaakov that he (not Esav) is the special offspring who will be the inheritor. Yitzchak himself was Avraham's special offspring and inheritor (even though Avraham had other children as well).

Sforno adds that when the offspring are righteous, they will be worthy of inheriting the land of Israel. They will be a .Kiddush HaShem", sanctification of God's name as opposed to a Chilul HaShem, desecration of God's name.

It is our mission to fulfill this blessing by accepting the land of Israel as our inheritance. In order to hold on to the land of Israel, the Jewish people in Israel and abroad must serve as an "Or Lagoyim", a light to the nations, a true sanctification of God's name.