At the end of this Parsha, Avraham takes another wife named Keturah who bears him six additional sons. Rashi explains that she was actually Hagar, whom he was essentially remarrying after having sent her away years before. According to Abarbanel it was understandable for him to remarry her after the death of Sara. Abarbanel is puzzled, however, by the fact that the Torah tells us explicitly that there were children from his concubines (plural), to whom he gave gifts. This is a clear indication that Hagar and Keturah were not the same person. What need did Avraham have for an additional wife besides Hagar?
Abarbanel provides six different reasons for Avraham’s actions. Firstly, G-d had already told Avraham, “You shall be the father of a multitude of nations.” (Bereishet 17:4) The six sons of Keturah and their progeny would end up in different places and represent the fulfillment of that promise. Secondly, having more children was a demonstration that undergoing brit mila did not diminish his ability to father more children. Thirdly, this was a way to prevent Yishmael from having any claim to an inheritance from Avraham. When Yishmael sees that Avraham sends away the sons of Keturah with gifts, rather than receiving an inheritance, he understands that he is, at best, on a par with them. Their mother Keturah has a higher status than his mother Hagar, as Hagar was merely Sara’s maidservant while Keturah is closer to a full wife in her own right. Still, they are sent away with only gifts, not a full inheritance.
Fourthly, taking Keturah as a wife demonstrates the difference between the nature of his marriage to Sara and this second marriage to Keturah. He was careful for both himself and Yitzchak to choose a wife from his own family in order to fulfill the covenant with G-d. Keturah was either a Canaanite, a Philistine or an Egyptian. With Yitzchak, however, Avraham was adamant that Eliezer his servant not find him a wife from the neighboring Canaanites, but only from Avraham’s family. His marriage to Keturah, on the other hand, was for himself. He knew that the future of the Jewish nation did not depend on her progeny. Fifthly, starting a new family in his old age and then sending them away without an inheritance provided reassurance to Yitzchak that he was Avraham’s sole heir. Normally, children born to a man in his old age have a special place in man’s heart, all the more so when the mother of the first sons has passed away. Yitzchak now has an ironclad guarantee that the nation will continue its development solely through him. Finally, Avraham was also trying to minimize the possibility of any further friction between Yitzchak and Yishmael. There is no question that Yishmael still harbored hatred for Yitzchak, since it was on account of Yitzchak that Yishmael was banished and supplanted as Avraham’s inheritor. By having more sons who would be sent away with gifts only, Avraham was demonstrating to Yishmael that Yitzchak’s favored status was not due to Sara; rather it was due to a prophecy that came directly from G-d. The Torah makes it clear that Avraham sent the children of the concubines away with gifts, with no mention of Yishmael being sent away also, even though Avraham must have given him gifts as well. Therefore, Yitzchak and Yishmael remained together in a brotherly relationship. Avraham dies at a good old age, mature and content, seeing Yishmael and Yitzchak reunited peacefully. They bury him together, only the two of them, with no mention of the sons of Keturah.