[Machine] Umrah bint Hamzah bin Abdul-Muttalib lived in Mecca. When the Messenger of Allah ﷺ arrived, specifically during the Umrah al-Qadhiyah, Ali ibn Abi Talib divorced her and the Prophet ﷺ said to marry her. The daughter of my brother was nursing, so the Messenger of Allah ﷺ married her off to Salamah ibn Abi Salamah. The Prophet ﷺ used to say, "Did you repay Salamah for this?" This is a weak chain of narration, and there is no mention that she was young. The Messenger of Allah ﷺ had the authority in matters of marriage that others did not have, and he was more eligible to marry her than her own uncle, Abbas ibn Abdul-Muttalib, if he had done so, and Allah knows best.  

أَنَّ عُمَارَةَ بِنْتِ حَمْزَةَ بْنِ عَبْدِ الْمُطَّلِبِ كَانَتْ بِمَكَّةَ فَلَمَّا قَدِمَ رَسُولُ اللهِ ﷺ يَعْنِي فِي عُمْرَةِ الْقَضِيَّةِ خَرَجَ بِهَا عَلِيُّ بْنُ أَبِي طَالِبٍ ؓ وَقَالَ النَّبِيُّ ﷺ تَزَوَّجْهَا فَقَالَ ابْنَةُ أَخِي مِنَ الرَّضَاعَةِ فَزَوَّجَهَا رَسُولُ اللهِ ﷺ سَلَمَةَ بْنَ أَبِي سَلَمَةَ فَكَانَ النَّبِيُّ ﷺ يَقُولُ هَلْ جُزِيتَ سَلَمَةَ هَذَا إِسْنَادٌ ضَعِيفٌ وَلَيْسَ فِيهِ أَنَّهَا كَانَتْ صَغِيرَةً وَلِلنَّبِيِّ ﷺ فِي بَابِ النِّكَاحِ مَا لَيْسَ لِغَيْرِهِ وَكَانَ أَوْلَى بِالْمُؤْمِنِينَ مِنْ أَنْفُسِهِمْ وَبِذَلِكَ تَوَلَّى تَزْوِيجَهَا دُونَ عَمِّهَا الْعَبَّاسِ بْنِ عَبْدِ الْمُطَّلِبِ إِنْ كَانَ فَعَلَ ذَلِكَ وَاللهُ أَعْلَمُ