This is the account of Abraham’s son Ishmael, whom Hagar the Egyptian, Sarah’s maidservant, bore to Abraham.
12. Now these are the generations of Ishmael. This narration is not superfluous. In the commencement of the chapter, Moses alludes to what was done for the sons of Keturah. Here he speaks designedly more at large, for the purpose of showing that the promise of God, given in the seventeenth chapter (Genesis 17:1-22,) was confirmed by its manifest accomplishment.
Immediately after the account of Abraham's death, Moses begins the story of Isaac (Gen 25:11), and tells us where he dwelt and how remarkably God blessed him. Note, The blessing of Abraham did not die with him, but survived to all the children of the promise.
Commenting on Genesis 25:11-18
Now these are the generations of Ishmael, Abraham's son,.... Or the genealogy of his posterity; and which is given to show that the Lord was not unmindful of his promise made to Abraham, concerning the multiplication of his seed, Gen 16:10, whom Hagar the Egyptian, Sarah's handmaid, bare unto Abraham; see Gen 16:1.