Fatima came to the Prophet ﷺ asking for a servant. He said, "May I inform you of something better than that? When you go to bed, recite "Subhan Allah' thirty three times, 'Al hamduli l-lah' thirty three times, and 'Allahu Akbar' thirty four times. ʿAli added, 'I have never failed to recite it ever since." Somebody asked, "Even on the night of the battle of Siffin?" He said, "Even on the night of the battle of Siffin."  

أَنَّ فَاطِمَةَ عَلَيْهَا السَّلاَمُ أَتَتِ النَّبِيَّ ﷺ تَسْأَلُهُ خَادِمًا فَقَالَ أَلاَ أُخْبِرُكِ مَا هُوَ خَيْرٌ لَكِ مِنْهُ تُسَبِّحِينَ اللَّهَ عِنْدَ مَنَامِكِ ثَلاَثًا وَثَلاَثِينَ وَتَحْمَدِينَ اللَّهَ ثَلاَثًا وَثَلاَثِينَ وَتُكَبِّرِينَ اللَّهَ أَرْبَعًا وَثَلاَثِينَ ثُمَّ قَالَ سُفْيَانُ إِحْدَاهُنَّ أَرْبَعٌ وَثَلاَثُونَ فَمَا تَرَكْتُهَا بَعْدُ قِيلَ وَلاَ لَيْلَةَ صِفِّينَ قَالَ وَلاَ لَيْلَةَ صِفِّينَ  

“Shall I not tell you of something that is better for you than that? Say Subhanallah thirty-three times, Allahu Akbar thirty-three times and Alhamdulillah thirty-three times; one of them thirty-four times.ʿ  

أَنَّ فَاطِمَةَ أَتَتِ النَّبِيَّ ﷺ تَسْتَخْدِمُهُ فَقَالَ أَلا أَدُلُّكِ عَلَى مَا هُوَ خَيْرٌ لَكِ مِنْ ذَلِكَ تُسَبِّحِينَ ثَلاثًا وَثَلاثِينَ وَتُكَبِّرِينَ ثَلاثًا وَثَلاثِينَ وَتَحْمَدِينَ ثَلاثًا وَثَلاثِينَ أَحَدُهَا أَرْبَعًا وَثَلاثِينَ  

The Messenger of Allah ﷺ came to us one night and put his foot between me and Fatimah, and he taught us what to say when we went to bed. Thirty-three tasbeehah, thirty-three tahmeedah and thirty-four takbeerah. ʿAli ؓ said: I never omitted it after that. A man said to him: Not even on the night of Siffeen? said: Not even on the night of Siffeen.  

أَتَانَا النَّبِيُّ ﷺ ذَاتَ لَيْلَةٍ حَتَّى وَضَعَ قَدَمَهُ بَيْنِي وَبَيْنَ فَاطِمَةَ فَعَلَّمَنَا مَا نَقُولُ إِذَا أَخَذْنَا مَضَاجِعَنَا ثَلاثًا وَثَلاثِينَ تَسْبِيحَةً وَثَلاثًا وَثَلاثِينَ تَحْمِيدَةً وَأَرْبَعًا وَثَلاثِينَ تَكْبِيرَةً قَالَ عَلِيٌّ فَمَا تَرَكْتُهَا بَعْدُ فَقَالَ لَهُ رَجُلٌ وَلا لَيْلَةَ صِفِّينَ؟ قَالَ وَلا لَيْلَةَ صِفِّينَ