Musannaf Ibn Abi Shayba 21:224

Waki’ narrated to us, from Shu’bah, from al-Hakam, from ‘Abd al-Rahman ibn Abi Layla, from ‘Ali, that Fatimah complained to the Prophet, may Allah bless him and grant him peace, about her hand from the dough and the hand-mill. He said: Then some captives arrived for the Prophet, may Allah bless him and grant him peace, so she came to him asking him for a servant, but she did not find him, and she found ‘Aishah and informed her. ‘Ali said: He came to us after we had taken to our beds, so we went to get up, but he said: "Stay where you are." He said: So he came and sat between me and her until I felt the coolness of his feet. He said: "Shall I not guide you both to that which is better for you than a servant? Glorify Allah (say SubhanAllah) thirty-three times, praise Him (say Alhamdulillah) thirty-three times, and magnify Him (say Allahu Akbar) thirty-three times."