Keturah was a wife of Abraham, after the death of Sarah, and after Abraham and Sarah's son Isaac had married Rebekah. Abraham and Keturah had six sons, who Abraham later sent away from what became the land of Israel (the God-commanded property of the descendants of Abraham, Isaac and Jacob - who God renamed Israel) where they founded some of the Arabian nations of today.
Sarah Dies, Isaac Marries Rebekah, Abraham Marries Keturah
Abraham had already taken a concubine, Hagar, who became the mother of Ishmael, at the instigation of Sarah herself before Isaac was born, when she thought that she could not have children of her own. After Sarah died however, Abraham married again.
"Sarah lived a hundred and twenty-seven years; these were the years of the life of Sarah. And Sarah died at Kiriath-arba, that is, Hebron, in the land of Canaan; and Abraham went in to mourn for Sarah and to weep for her." (Genesis 23:1-2 RSV)
"And Rebekah lifted up her eyes, and when she saw Isaac, she alighted from the camel, and said to the servant, "Who is the man yonder, walking in the field to meet us?" The servant said, "It is my master." So she took her veil and covered herself. And the servant told Isaac all the things that he had done. Then Isaac brought her into the tent, and took Rebekah, and she became his wife; and he loved her. So Isaac was comforted after his mother's death." (Genesis 24:64-67 RSV)
"Abraham took another wife, whose name was Keturah. She bore him Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah." (Genesis 25:1-2 RSV)
The Sons Of Keturah Formed Their Own Nations
Abraham became the "father of many nations" through his descendants of the Keturah line, as well as those through Ishmael. But the land of Israel was, according to God's Will, to be the inheritance of Isaac:
"Abraham gave all he had to Isaac. But to the sons of his concubines Abraham gave gifts, and while he was still living he sent them away from his son Isaac, eastward to the east country." (Genesis 25:5-6 RSV)
Fact Finder: Midian was one of the sons of Keturah. Centuries after Abraham, did Moses marry and have children with Zipporah, the daughter of Jethro the Midianite?