Sunan an-Nasa'i, Volume 4, Book 26, Hadith 3223 (DarusSalam) ⓘ

Narrated 'Abdullah bin Buraidah: It was narrated from 'Abdullah bin Buraidah that his father said: "Abu Bakr and 'Umar, may Allah be pleased with them, proposed marriage to Fatimah but the Messenger of Allah said: 'She is young.' Then 'Ali proposed marriage to her and he married her to him."

أَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ حَدَّثَنَا الْفَضْلُ بْنُ مُوسَى، عَنِ الْحُسَيْنِ بْنِ وَاقِدٍ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، قَالَ خَطَبَ أَبُو بَكْرٍ وَعُمَرُ رضى الله عنهما فَاطِمَةَ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ إِنَّهَا صَغِيرَةٌ ‏" ‏ ‏.‏ فَخَطَبَهَا عَلِيٌّ فَزَوَّجَهَا مِنْهُ ‏.‏