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. (Using translation from Aḥmad 1229)
أَتَانَا رَسُولُ اللَّهِ ﷺ حَتَّى وَضَعَ قَدَمَهُ بَيْنِي وَبَيْنَ فَاطِمَةَ فَعَلَّمَنَا مَا نَقُولُ إِذَا أَخَذْنَا مَضَاجِعَنَا ثَلَاثًا وَثَلَاثِينَ تَسْبِيحَةً وَثَلَاثًا وَثَلَاثِينَ تَحْمِيدَةً وَأَرْبَعًا وَثَلَاثِينَ تَكْبِيرَةً قَالَ عَلِيٌّ «فَمَا تَرَكْتُهَا بَعْدُ» فَقَالَ لَهُ رَجُلٌ وَلَا لَيْلَةَ صِفِّينَ؟ قَالَ «وَلَا لَيْلَةَ صِفِّينَ»