Genesis 12:2

וְאֶעֶשְׂךָ לְגוֹי גָּדוֹל וַאֲבָרֶכְךָ וַאֲגַדְּלָה שְׁמֶךָ וֶהְיֵה בְּרָכָה

I will make you into a great nation, and I will bless you and make your name great, and you will be a blessing.

How would Avraham’s name be made great? Rabbi Joseph B. Soloveitchik explained that Yitzchak and Yaakov would build upon the religious methodologies pioneered by Avraham. This is comparable to the way the Tosafists said that their renowned work in Torah study could never have existed without the foundation laid for them by Rashi. (Cited in the Mesoras HaRav Chumash.)