מדרש הגדול, בראשית מ"ה:כ"ו
ויגדו לו לאמר 'עוד יוסף חי' רבנן אמרו אם אנו אומרים לו תחלה יוסף קים שמא תפרח נשמתו. מה עשו? אמרו לשרח בת אשר, "אמרי לאבינו יעקב שיוסף קים והוא במצרים. מה עשתה? המתינה לא עד שהוא עומד בתפלה ואמרה בלשון תימה:
- יוסף במצרים
- יולדו לו על ברכים
- מנשה ואפרים
פג לבו כשהוא עומד בתפלה. כיון שהשלים ראה העגלות, מיד "ותחי רוח יעקב אבינו" (שם).
Midrash HaGadol, Genesis 45:26
[The brothers said:]If we tell him right away, "Joseph is alive!" perhaps he will have a stroke [lit., his soul will fly away]. What did they do? They said to Serah, daughter of Asher, "Tell our father Jacob that Joseph is alive, and he is in Egypt." What did she do? She waited till he was standing in prayer, and then said in a tone of wonder, "Joseph is in Egypt/ There have been born on his knees/ Menasseh and Ephraim" [three rhyming lines]. His heart failed, while he was standing in prayer. When he finished his prayer, he saw the wagons: immediately the spirit of Jacob came back to life.(Translated by Avivah Zornberg in Genesis, the Beginning of Desire, p.281).
The Persian Jews of the city of Isfahan believed that Serah bat Asher actually lived among them until she died in a great fire in their synagogue in the twelfth century CE. This synagogue and its successors were subsequently known as the Synagogue of Serah Bat Asher. In the Jewish cemetery of Isfahan, there was to be found, at least until the end of the nineteenth century, a tombstone marking the final resting place of "Serah the daughter of Asher the son of our Patriarch Jacob" who died in the year equivalent to 1133 CE. This alleged gravesite was marked by a small mausoleum known as heder Serah ("Serah's Room"), which remained for centuries one of the best known pilgrimage sites for the Jews of Persia. In the Iranian exile, Jews were accustomed to prostrate themselves at the gravestone of Serah, as they now customarily pray here in Israel at the Tomb of our Matriarch Rachel near Bethlehem. Like the tomb of Rachel, that of Serah is also located in a "room" (i.e., a mausoleum). This room is believed to have wondrous doorposts and only people of good character and deeds may enter; but the way in shrinks before anyone else and prevents them from entering.
Marc Bregman, Serah bat Asher: Biblical Origins, Ancient Aggadah and Contemporary Folklore, The Bilgray Lectureship, booklet published and distributed by the University of Arizona, 1997 [reprinted in New Harvest (St. Louis: The Brodsky Library Press, 2005)].