Musnad Ahmad 480
`Uthman bin `Affan (رضي الله عنه) said to his nephew:
Did you meet the Messenger of Allah (ﷺ)? He said: No, but there reached me of his knowledge and certainty of faith that which would reach a virgin in her seclusion .He [`Uthman] recited the tashahhud then he said: Verily Allah, may He be glorified and exalted, sent Muhammad  with the truth and I was one of those who responded to (the call of) Allah and His Messenger, and I believed in that with which Muhammad (ﷺ) was sent. Then I migrated twice, and I also attained the honour of becoming the son-in law of the Messenger of Allah (ﷺ), I swore allegiance to the Messenger of Allah (ﷺ), and by Allah, I never disobeyed him or betrayed him until Allah, may He be glorified and exalted, took his soul in death.
حَدَّثَنَا بِشْرُ بْنُ شُعَيْبٍ، حَدَّثَنِي أَبِي، عَنِ الزُّهْرِيِّ، حَدَّثَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ عُبَيْدَ اللَّهِ بْنَ عَدِيِّ بْنِ الْخِيَارِ، أَخْبَرَهُ أَنَّ عُثْمَانَ بْنَ عَفَّانَ رَضِيَ اللَّهُ عَنْهُ قَالَ لَهُ ابْنَ أَخِي أَدْرَكْتَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ فَقُلْتُ لَهُ لَا وَلَكِنْ خَلَصَ إِلَيَّ مِنْ عِلْمِهِ وَالْيَقِينِ مَا يَخْلُصُ إِلَى الْعَذْرَاءِ فِي سِتْرِهَا قَالَ فَتَشَهَّدَ ثُمَّ قَالَ أَمَّا بَعْدُ فَإِنَّ اللَّهَ عَزَّ وَجَلَّ بَعَثَ مُحَمَّدًا صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالْحَقِّ فَكُنْتُ مِمَّنْ اسْتَجَابَ لِلَّهِ وَلِرَسُولِهِ وَآمَنَ بِمَا بُعِثَ بِهِ مُحَمَّدٌ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ ثُمَّ هَاجَرْتُ الْهِجْرَتَيْنِ كَمَا قُلْتُ وَنِلْتُ صِهْرَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَبَايَعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَوَاللَّهِ مَا عَصَيْتُهُ وَلَا غَشَشْتُهُ حَتَّى تَوَفَّاهُ اللَّهُ عَزَّ وَجَلَّ‏.‏