Musannaf Ibn Abi Shayba 19:738

Abu Bakr narrated to us, he said: Affan bin Muslim narrated to us, he said: Aban al-Attar narrated to us, he said: Yahya bin Abi Kathir narrated to me, from Abu Qilabah, from Abu al-Muhallab, from Imran bin Husayn, that a woman from Juhaynah came to the Prophet, may Allah bless him and grant him peace, and said: "I have committed a transgression (hadd), so execute it upon me," and she was pregnant. He ordered that she be treated well until she gave birth. When she had given birth, she was brought to the Messenger of Allah, may Allah bless him and grant him peace. He ordered that her clothes be removed from her, then he stoned her and prayed over her. Umar said: "O Prophet of Allah, do you pray over her when she has committed adultery?" He said: "She has repented with a repentance that, if it were divided among seventy of the people of Medina, it would suffice them. And have you found anything better than that she offered her soul?"