The Prophet met 'Uthman at the door of the mosque and said: "O 'Uthman! Jibril has told me that Allah married you to Umm Kulthum for a dowry like that of Ruqayyah, provided that you treat her as you treated Ruqayyah."

أَنَّ النَّبِيَّ ﷺ لَقِيَ عُثْمَانَ عِنْدَ بَابِ الْمَسْجِدِ فَقَالَ يَا عُثْمَانُ هَذَا جِبْرِيلُ أَخْبَرَنِي أَنَّ اللَّهَ قَدْ زَوَّجَكَ أُمَّ كُلْثُومٍ بِمِثْلِ صَدَاقِ رُقَيَّةَ عَلَى مِثْلِ صُحْبَتِهَا