Let me guide you to something better than what you asked for. When you go to bed, say ‘Subhān Allah' (glory be to Allah) thirty-three times, ‘Alhamdulillāh' (praise be to Allah) thirty-three times, and ‘Allāhu Akbar' (Allah is the Most Great) thirty-four times. This is better for you than a servant

Fātimah (may Allah be pleased with her), the Prophet's daughter, complained about the effect of the grinding-stone on her hand. When captives were brought to the Prophet (may Allah's peace and blessings be upon him), she rushed to ask him for a servant from these captives so as to do the household chores on her behalf. She, however, did not find him and found ‘Ā’ishah (may Allah be pleased with her). She told her about the matter.

When he (may Allah's peace and blessings be upon him) came, ‘Ā’ishah told him that Fātimah had come to ask him for a servant. So, the Prophet (may Allah's peace and blessings be upon him) came to Fātimah and ‘Ali (may Allah be pleased with both of them) at their house while they were in bed, preparing to sleep. He sat down between them, and ‘Ali (may Allah be pleased with him) felt the coldness of the Prophet's feet on his belly.

He said: Shall I teach you something better than what you have asked me for giving you a servant? They replied in the affirmative. So, he (may Allah's peace and blessings be upon him) said: When you go to bed for sleep in the night, say Takbīr thirty-four times: Allāhu Akbar. Glorify Allah thirty-three times, saying: Subhān Allah. And praise Allah thirty-three times, saying: Alhamdulillāh. This Dhikr is better for you than having a servant.