וַיַּ֨עַן יִצְחָ֜ק וַיֹּ֣אמֶר לְעֵשָׂ֗ו הֵ֣ן גְּבִ֞יר שַׂמְתִּ֥יו לָךְ֙ וְאֶת־כָּל־אֶחָ֗יו נָתַ֤תִּי לוֹ֙ לַעֲבָדִ֔ים וְדָגָ֥ן וְתִירֹ֖שׁ סְמַכְתִּ֑יו וּלְכָ֣ה אֵפ֔וֹא מָ֥ה אֶֽעֱשֶׂ֖ה בְּנִֽי׃
At sumagot si Isaac at sinabi kay Esau: “Narito, ginawa ko siyang panginoon mo, at ibinigay ko sa kanya ang lahat ng kanyang mga kapatid bilang mga alipin, at tinustusan ko siya ng butil at alak. At para sa iyo, ano pa nga ang magagawa ko, anak ko?”
Rashi
הן גביר AND BEHOLD I HAVE MADE HIM THY MASTER — This blessing is the seventh in the series of blessings which Isaac gave to Jacob (cf. w. 28. 29) and yet he (Isaac) singles it out as though it were the chief blessing? But the explanation is, he said to him (Esau): “What benefit will a blessing be to you? If you acquire property, it will belong to him, for “Behold, I have made him thy master״, and whatever a servant acquires becomes the property of his master (Genesis Rabbah 67:5).
Chizkuni
ואת כל אחיו, “and all his brothers, etc.;” Yitzchok refers to Yishmael and his extended family and the children of Keturah.
Da'at Zekenim
ולכה איפוא, what then can I do for you? the word ולכה here is spelled with the letter ה at the end, (numerical value of 5) something most unusual; Yitzchok hinted to Esau that after 5000 years of human history will have passed his descendants will achieve superiority on earth, but that seeing that he, Esau, will wind up in Gehinom, he, his father, cannot do anything in the meantime to interfere with G–d’s decree.