Very little is known about Keturah (Gen. 25:1). Rashi identifies her with Hagar while Rashbam, Ramban, Ibn Ezra and others argue that she was Abraham’s third wife. Contrary to Midrashic and early rabbinic tradition, there can be little doubt that based on the genealogy of 1 Chronicles 1:32, Hagar and Keturah were two separate women.
Although Abraham would later insist that Eliezer not find Isaac a wife among the Canaanite women, that was essential for Isaac, for only he was considered the rightful heir of Abraham, but the children of the concubines were not. As to her place of origin, the Torah does not mention which people she originated from and this would probably suggest that she was a Canaanite. Sensing the scandalous implications of this interpretation, Bahya writes:
“Don’t ask how it was possible for Abraham to marry a local Canaanite woman after he specifically made Eliezer that he would not take a Canaanite woman for his son Isaac. The proscription never applied to anyone else but Isaac, who was yet to carry out the lineage of Abraham . . . Once Isaac was married, there was no reason why Abraham couldn’t marry any woman presuming she was a suitable mate for him and was a woman of virtue . . .” 
Whether Keturah might was of Canaanite origin is questionable; it is possible that she might have been from another non-Canaanite people who inhabited the such as the Perizzites or the Hittites, or from any one of the peoples who inhabited the Arabian peninsula. Little is said about her background, for after all, she was only a concubine who did not come from a family of distinction.
 As explained by Abarbanel, Ramban, and others.
 Judging from Rashi’s commentary to 1 Chronicles 1:32, it would appear Rashi did not sense the inherent contradiction posed by his view that Hagar and Keturah were one and the same person. Rashi writes is “And the sons of Keturah, Abraham’s concubine . . . Anything disgraceful that he could tell about them, the narrator relates these details in order to enhance Isaac’s honor, i.e., they were all the children of a concubine, but he [Isaac] was the mainstay and the master of the household.”
 Bahya’s interpretation of this verse is based upon Ramban’s commentary.