Mishkat al-Masabih 2387
‘Ali said that Fatima went to the Prophet to complain of the effect of the grinding-stone on her hand, as she had heard that he had acquired some slaves, but did not find him, so she mentioned the matter to ‘A'isha. When he came ‘A'isha informed him. ‘Ali said:
He visited us when we had gone to bed, and when we were about to get up he told us to stay where we were. He then came and sat down between her and me, and I felt the coldness of his foot on my belly. He then said, “Let me guide you to something better than what you have asked. When you go to bed, say ‘Glory be to God’ thirty-three times, ‘Praise be to God’ thirty-three times, and ‘God is most great’ thirty-four times. That will be better for you than a servant.” 

(Bukhari and Muslim.)
وَعَن عَليّ: أَن فَاطِمَة أَنْت النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ تَشْكُو إِلَيْهِ مَا تَلْقَى فِي يَدِهَا مِنَ الرَّحَى وَبَلَغَهَا أَنَّهُ جَاءَهُ رَقِيقٌ فَلَمْ تُصَادِفْهُ فَذَكَرَتْ ذَلِكَ لِعَائِشَةَ فَلَمَّا جَاءَ أَخْبَرَتْهُ عَائِشَةُ قَالَ: فَجَاءَنَا وَقَدْ أَخَذْنَا مَضَاجِعَنَا فَذَهَبْنَا نَقُومُ فَقَالَ: عَلَى مَكَانِكُمَا فَجَاءَ فَقَعَدَ بَيْنِي وَبَيْنَهَا حَتَّى وَجَدْتُ بَرْدَ قَدَمِهِ عَلَى بَطْنِي فَقَالَ: «أَلَا أَدُلُّكُمَا عَلَى خَيْرٍ مِمَّا سَأَلْتُمَا؟ إِذَا أَخَذْتُمَا مَضْجَعَكُمَا فَسَبِّحَا ثَلَاثًا وَثَلَاثِينَ وَاحْمَدَا ثَلَاثًا وَثَلَاثِينَ وَكَبِّرَا ثَلَاثًا وَثَلَاثِينَ فَهُوَ خير لَكمَا من خَادِم»