The Torah portion discusses Abraham’s marriage to a woman named Ketura. Who was she?

“Abraham took another wife, and her name was Ketura” (Genesis 25:1). Rabbi Yehuda says: This is in fact Hagar…But isn’t it written: “And her name was Ketura”? It is because she attached herself [shekatra] to mitzvot and good deeds. (Yalkut Shimoni, Vayetze 109)