When the wicked kingdom destroyed the Temple and carried the people into slavery, the son and daughter of Rabbi Ishmael — both famous for their beauty — were seized and sold to different Roman masters.
The masters, who did not know they were siblings, met and schemed together. "Let the boy and girl be locked in one room overnight," they said. "From such perfect beauty we will breed children still more beautiful, and make a great profit when we sell them at market." So the two young captives were pushed into a single cell and the door was barred.
Neither knew who the other was. Each, raised in the home of Rabbi Ishmael, understood the Torah's laws of modesty and intimacy. All through the night they sat at opposite walls, weeping quietly and refusing even to speak, lest they be drawn into sin.
At dawn the first light fell across the cell, and in that light each looked up, and in that same instant each recognized the other's face. Brother and sister. They rushed across the room and fell into each other's arms, and their hearts broke — broke so violently from grief and relief together that their souls left their bodies where they stood. They died, the sages say, in one embrace.
The Exempla preserves the tale as an indictment of the cruelty of Rome and as a testament to the holiness of Rabbi Ishmael's house — where the children, even naked and alone, kept the law of their father so faithfully that death found them clean.
(From The Exempla of the Rabbis, Moses Gaster, 1924, no. 59, based on the martyrological traditions of Gittin 58a.)