And ESAU said unto his father, Hast thou but one blessing, my father? Not as desiring either the reversal of the patriarchal sentence upon Jacob, which he appears to have understood to be irrevocable, or an extension of its gracious provisions, so as to include him as well as Jacob; but as soliciting such a benediction as would place him, at least in respect of temporalities, on a level with the favorite of Rebekah, either because he did not recognize the spiritual character of the covenant blessing, or because, though recognizing it, he was willing to let it go.
Bless me, even me also, O my father. And Esau lifted up his voice, and wept (cf. Hebrews 12:17). "Those tear expressed, indeed, sorrow for his forfeiture, but not for the sinful levity by which it had been incurred.
They were ineffectual (i.e. they did not lead to genuine repentance) because Esau was incapable of true repentance" (vide Delitzsch on Hebrews 12:17).