Abraham remarries and Ishmael's descendants
Abraham marries again after Sarah dies. There is no commandment against marriage in old age or once the first spouse has passed on. We see here that the promise of many children is partly kept with 6 more sons from Keturah. I don't know if this is wise considering some of their descendants became enemies of the Hebrews, but then again, the Hebrews fought against each other from time to time.
Abraham gives the inheritance to Isaac as was part of the God's plan and part of the promise already made to Isaac and even Rebekah when she was found and brought to Isaac. Abraham did provide for Ishmael and his other sons, but not part of the larger inheritance.
Isaac and Ishmael bury Abraham with Sarah in the land purchased previously. It appears that Isaac and Ishmael did get along at least to some degree. We learn about the descendants of Ishmael and then his death. God blessed him to live many years (130), at least by our standards.
We see as Isaac goes on with his life that like his mother, Rebekah has trouble conceiving. We will encounter many of the same problems in our life that our parents and their parents before them. Like the example set by Abraham, we need to take our petitions to the Lord and pray that his will is done. Rebekah conceives and while she is baring the child she finds out there are two babies to be born. They seem to fight in her womb and God tells her that there are two in her womb and they and their seed will fight one another. Great is God's vision of the future because it already is laid out before him.
Esau is born, then Jacob soon after holding onto the heal of Esau. This was a special moment that had deep significance to them both. The elder is usually the ruler in the family, but we see here that was not going to be the case. As often happens, parents take sides or have favorites and Isaac's favorite was Esau and Rebekah's was Jacob. We will come to more of that in future chapters, but at the end of this one, Esau comes in faint from the fields and sells his birthright to Jacob. What God gives us, lets all hold it dear to our hearts and never sell it or give it away because he might be faint of heart.