Musnad Ahmad 5:178

Waki’ narrated to us, Shu’bah narrated to us, from al-Hakam, from ‘Abd al-Rahman ibn Abi Layla, ‘Ali narrated to us, that Fatimah complained to the Prophet, may Allah bless him and grant him peace, about the effect of the dough on her hand. The Prophet, may Allah bless him and grant him peace, was brought some captives, so she went to him to ask him for a servant, but she did not find him, so she returned. He said: He came to us when we had taken to our beds. I went to stand up, but he said: "Stay where you are." He came and sat down 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? When you take to your beds, glorify Allah thirty-three times, praise Him thirty-three times, and magnify Him thirty-four times."