וְיִֽתֶּן־לְךָ֙ אֶת־בִּרְכַּ֣ת אַבְרָהָ֔ם לְךָ֖ וּלְזַרְעֲךָ֣ אִתָּ֑ךְ לְרִשְׁתְּךָ֙ אֶת־אֶ֣רֶץ מְגֻרֶ֔יךָ אֲשֶׁר־נָתַ֥ן אֱלֹהִ֖ים לְאַבְרָהָֽם׃
און ער װעט דיר געבן די ברכה פֿון אבֿרהמען, דיר און דײַן זאָמען מיט דיר, כּדי זאָלסט אַרבן דאָס לאַנד פֿון דײַן װױנשאַפֿט, װאָס גאָט האָט געגעבן צו אבֿרהמען.
Rashi
את ברכת אברהם THE BLESSING OF ABRAHAM, (i. e. the blessing which He gave to (Abraham) to whom He promised, (12:2) “and I will make of thee a great nation”, and (26:4) “and all the nations shall bless themselves by thy seed”: may these blessings have been said regarding you — may that great nation and that blessed seed issue from you.
Chizkuni
לרשתך את ארץ מגוריך, “to give you as an inheritance the land in which you presently are sojourning.” Seeing that you must not take a wife from the present occupiers of this land, Yitzchok had to reconfirm this. Not only that, he implied that seeing the Canaanites, ever since having been cursed by Noach, were a nation of slaves, slaves could not claim legal title to any possessions.
Rashbam
לרשתך את הארץ, seeing that you cannot take a wife from the daughters of the Canaanites as Avraham had commanded Yitzchok because they are slaves, (cursed.)