Hadith 3255
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا أَبُو مُعَاوِيَةَ، قَالَ حَدَّثَنَا هِشَامُ بْنُ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم تَزَوَّجَهَا وَهِيَ بِنْتُ سِتٍّ وَبَنَى بِهَا وَهِيَ بِنْتُ تِسْعٍ .
It was narrated from 'Aishah that the Messenger of Allah married her when she was six years old, and consummated the marriage with her when she was nine.
Reference : Sunan an-Nasa'i 3255
In-book reference : Book 26, Hadith 60