이사야 8:5의 미드라쉬

And her name was Keturah: Rav said, "She is Hagar." Rabbi Nechemiah said to him, "And is it not written, 'he added.'" He said to him, "[That signifies that] he [now] married her according to the [Divine] word; like that which you say (Isaiah 8), 'And the Lord added to speak to me more.'" He said to him, "And is it not written, 'And her name was Keturah?'" He said to him, "[It is] since she was fragrant (mekuteret) with commandments and good deeds." He said to him, "And is it not written, 'And to the sons of the concubines that Avraham had?'" He said, "It is [actually] written, 'concubine' (in the singular, such that there only be one concubine - Hagar)." "While he was still alive (chai)" - [this is a reference to] the one that sat by the well and said to the Life (chai) of the worlds, "Look at my embarrassment!" Rabbi Berakhia said, "Even though you say (Genesis 21:14), 'and she went and strayed in the wilderness, etc., [such that] you would say that she was suspected with any [other man]; hence we learn to say, 'And her name was Keturah' - like a type of knot (ketur) like this, [with which] he seals a storehouse and opens it with a seal, [that is] tied and sealed." Bar Kapra said, "The addition of the Holy One, blessed be He, is greater than the main part: Kayin was was the main part and as a result of Hevel being the addition - as it is is written (Genesis 4:2), 'And she added to give birth' - he and his two twins were born; Yosef was the main part, and as a result of it being written, addition, with Binyamin, he established ten [children], as it is written (Genesis 46:21), ' And the children of Binyamin were Bela and Becher, etc.'; Er was the main part, and as a result of Shelah being [born] with the language of addition, he established ten [courts], behold, it is written in I Chronicles 4:21, 'And the sons of Shelah the son of Yehudah were Er, the father (a term that is also used for the head of a court) of Lecha, and Ladah, the father of Maresha, and the families of the house Avodat HaButs of the house of Ashbea'; the main part of the years of Iyov were only seventy years, [and] one hundred and forty years were added to him, as it is written (Job 42:16), 'And Iyov lived after this one hundred and forty years'; the main part of the reign of Chizkiyahu was only fourteen years, and fifteen years were added to him, as it states (Isaiah 38:), 'behold, I will add fifteen years to your days; Yishmael is the main part, and as a result of the children of Keturah being [born] with the language of addition, 'And she gave birth for him to Zimran, etc.'"