Sahih al-Bukhari 5134Book 67, Hadith 70
حَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ، حَدَّثَنَا وُهَيْبٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم تَزَوَّجَهَا وَهْىَ بِنْتُ سِتِّ سِنِينَ، وَبَنَى بِهَا وَهْىَ بِنْتُ تِسْعِ سِنِينَ. قَالَ هِشَامٌ وَأُنْبِئْتُ أَنَّهَا كَانَتْ عِنْدَهُ تِسْعَ سِنِينَ.
that the Prophet (ﷺ) married her when she was six years old and he consummated his marriage when she was nine years old. Hisham said: I have been informed that `Aisha remained with the Prophet (ﷺ) for nine years (i.e. till his death).