Umm Kulthum bint Thumamah al-Habati (may Allah have mercy on her) narrates that her brother, al-Mukhariq bin Thumamah al-Habati (may Allah have mercy on him), said to her: "Go to the Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), and convey my greeting of peace to her." So I went to her and said: "One of your sons conveys the greeting of peace to you." She said: "And upon him be peace and the mercy of Allah." I said: "He asks you to tell him about Sayyiduna Uthman bin Affan (may Allah be pleased with him), for since he was martyred, people among us have said a great deal about him." The Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), said: "As for me, I bear witness that Sayyiduna Uthman bin Affan (may Allah be pleased with him) was present in this house while Jibril (peace be upon him) was bringing revelation to the Prophet of Allah (peace and blessings be upon him). He (Jibril, peace be upon him) came to the Prophet (peace and blessings be upon him) on an intensely hot night, and whenever revelation came down upon him (peace and blessings be upon him), a heaviness would come upon him (peace and blessings be upon him). Allah, exalted be His remembrance, says: 'Indeed, We will cast upon you a weighty word.' And the Prophet of Allah (peace and blessings be upon him) was striking the shoulder of Sayyiduna Uthman (may Allah be pleased with him) and saying: 'Write, Uthman!' Allah Almighty grants this rank with His Prophet (peace and blessings be upon him) only to a noble and honourable man. So whoever reviles Sayyiduna Uthman (may Allah be pleased with him), upon him be the curse of Allah."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Umm Kulthum bint Thumamah (may Allah have mercy on her) except Hammad bin Ibrahim al-Yashkuri."
Hadith Referenceالمعجم الأوسط / باب العين / 3758
Hadith Gradingمحدثین:فيه أم كلثوم لم يعرفها الهيثمي، وبقية رجاله ثقات
Hadith Takhrij«قال الهيثمي: وأم كلثوم لم أعرفها وبقية رجال الطبراني ثقات «مجمع الزوائد ومنبع الفوائد، ج 9، ص 87»» «أخرجه أحمد فى «مسنده» برقم: 26771، 26888»