When the Prophet (ﷺ) set out for the Battle of Badr, she said, "I said, 'O Messenger of Allah, permit me to go out on the campaign with you; I will nurse your sick, and perhaps Allah might grant me martyrdom.' He said, 'Stay in your house, for Allah, the Exalted, will grant you martyrdom.'"
She was thus called the Martyr.
She had memorized the Qur'an and asked permission of the Prophet (ﷺ) to have a caller to prayer in her home, and he permitted her. She had arranged for her male slave and female slave to be free after her death, so they came to her by night and smothered her with a velvet sheet of hers until she died, and then they fled.
The next morning, Umar stood up among the people and said, "Whoever has any knowledge about these two, or whoever has seen them, let him bring them forth." So he gave orders concerning them, and they were crucified, being the first people to be crucified in Medina.