A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
gen 25:1SONS OF ABRAHAM. (Gen 25:1-6)
Abraham took a wife--rather, "had taken"; for Keturah is called Abraham's concubine, or secondary wife (Ch1 1:32); and as, from her bearing six sons to him, it is improbable that he married after Sarah's death; and also as he sent them all out to seek their own independence, during his lifetime, it is clear that this marriage is related here out of its chronological order, merely to form a proper winding up of the patriarch's history.
gen 25:5Abraham gave all that he had unto Isaac . . . unto the sons of the concubines . . . Abraham gave gifts--While the chief part of the inheritance went to Isaac; the other sons (Ishmael included) migrated to "the East country," that is, Arabia, but received each a portion of the patrimony, perhaps in cattle and other things; and this settlement of Abraham's must have given satisfaction, since it is still the rule followed among the pastoral tribes.
gen 25:7DEATH OF ABRAHAM. (Gen 25:7-11)
these are the days of . . . Abraham--His death is here related, though he lived till Jacob and Esau were fifteen years, just one hundred years after coming to Canaan; "the father of the faithful," "the friend of God" [Jam 2:23], died; and even in his death, the promises were fulfilled (compare Gen 15:15). We might have wished some memorials of his deathbed experience; but the Spirit of God has withheld them--nor was it necessary; for (see Mat 7:16) from earth he passed into heaven (Luk 16:22). Though dead he yet liveth (Mat 22:32).
gen 25:9his sons . . . buried him--Death often puts an end to strife, reconciles those who have been alienated, and brings rival relations, as in this instance, to mingle tears over a father's grave.
gen 25:18DESCENDANTS OF ISHMAEL. Before passing to the line of the promised seed, the historian gives a brief notice of Ishmael, to show that the promises respecting that son of Abraham were fulfilled--first, in the greatness of his posterity (compare Gen 17:20); and, secondly, in their independence. (Gen 25:12-18)
he died--rather, "it [their lot] fell" in the presence of his brethren (compare Gen 16:12).
gen 25:19HISTORY OF ISAAC. (Gen 25:19-34)
these are the generations--account of the leading events in his life.
gen 25:21Isaac entreated the Lord for his wife--Though tried in a similar way to his father, he did not follow the same crooked policy. Twenty years he continued unblessed with offspring, whose seed was to be "as the stars" [Gen 26:4]. But in answer to their mutual prayers (Pe1 3:7), Rebekah was divinely informed that she was to be the mother of twins, who should be the progenitors of two independent nations; that the descendants of the younger should be the more powerful and subdue those of the other (Rom 9:12; Ch2 21:8).
gen 25:27the boys grew--from the first, opposite to each other in character, manners, and habits.
gen 25:28The parents were divided in their affection; and while the grounds, at least of the father's partiality, were weak, the distinction made between the children led, as such conduct always does, to unhappy consequences.
gen 25:29Jacob sod pottage--made of lentils or small beans, which are common in Egypt and Syria. It is probable that it was made of Egyptian beans, which Jacob had procured as a dainty; for Esau was a stranger to it. It is very palatable; and to the weary hunter, faint with hunger, its odor must have been irresistibly tempting.
gen 25:31Jacob said, Sell me . . . thy birthright--that is, the rights and privileges of the first-born, which were very important, the chief being that they were the family priests (Exo 4:22) and had a double portion of the inheritance (Deu 21:17).
gen 25:32Esau said . . . I am at the point to die--that is, I am running daily risk of my life; and of what use will the birthright be to me: so he despised or cared little about it, in comparison with gratifying his appetite--he threw away his religious privileges for a trifle; and thence he is styled "a profane person" (Heb 12:16; also Job 31:7, Job 31:16; Job 6:13; Phi 3:19). "There was never any meat, except the forbidden fruit, so dear bought, as this broth of Jacob" [BISHOP HALL].