Sahih Muslim Book - 4, Hadith - 1089

وَحَدَّثَنِى حَسَنُ بْنُ عَلِىٍّ الْحُلْوَانِىُّ وَمُحَمَّدُ بْنُ رَافِعٍ قَالاَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ أَخْبَرَنَا ابْنُ جُرَيْجٍ قَالَ قُلْتُ لِعَطَاءٍ كَيْفَ تَقُولُ أَنْتَ فِى الرُّكُوعِ قَالَ أَمَّا سُبْحَانَكَ وَبِحَمْدِكَ لاَ إِلَهَ إِلاَّ أَنْتَ فَأَخْبَرَنِى ابْنُ أَبِى مُلَيْكَةَ عَنْ عَائِشَةَ قَالَتِ افْتَقَدْتُ النَّبِىَّ -صلى الله عليه وسلم- ذَاتَ لَيْلَةٍ فَظَنَنْتُ أَنَّهُ ذَهَبَ إِلَى بَعْضِ نِسَائِهِ فَتَحَسَّسْتُ ثُمَّ رَجَعْتُ فَإِذَا هُوَ رَاكِعٌ أَوْ سَاجِدٌ يَقُولُ « سُبْحَانَكَ وَبِحَمْدِكَ لاَ إِلَهَ إِلاَّ أَنْتَ ». فَقُلْتُ بِأَبِى أَنْتَ وَأُمِّى إِنِّى لَفِى شَأْنٍ وَإِنَّكَ لَفِى آخَرَ.

Ibn Juraij said: "I said to 'Ata': 'What do you say when you bow?' He said: 'Subhanaka wa bihamdika la ilaha ilia anta (Glory and praise be to You, there is none worthy of worship except You.) Ibn Abi Mulaikah told me that 'Aishah said: "I noticed that the Prophet (s.a.w) was not there one night, and I thought that he had gone to one of his (other) wives. I looked for him, then I came back, and I saw he was bowing or prostrating and saying: 'Subhanaka wa bihamdika Ia ilaha ilia anta (Glory and praise be to You, there is none worthy of worship except You.)' I said: 'May my father and mother be sacrificed for you! I was thinking of one thing and you were doing something else."'