Musnad Ahmad 475
It was narrated from Yazeed bin Mawhab that `Uthman (رضي الله عنه) said to Ibn `Umar (رضي الله عنه). Judge between the people. He said:
I will not judge between two people or lead two men in prayer. Did you not hear the Prophet (ﷺ) say, `Whoever seeks refuge with Allah has indeed sought refuge with a powerful one`?`Uthman (رضي الله عنه) said. Yes I did. He said: then I seek refuge with Allah lest you appoint me to some post. So Uthman (رضي الله عنه) let him off and said: Do not tell anyone else about this.
حَدَّثَنَا عَفَّانُ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، أَنْبَأَنَا أَبُو سِنَانٍ، عَنْ يَزِيدَ بْنِ مَوْهَبٍ، أَنَّ عُثْمَانَ، رَضِيَ اللَّهُ عَنْهُ قَالَ لِابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُ اقْضِ بَيْنَ النَّاسِ فَقَالَ لَا أَقْضِي بَيْنَ اثْنَيْنِ وَلَا أَؤُمُّ رَجُلَيْنِ أَمَا سَمِعْتَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ مَنْ عَاذَ بِاللَّهِ فَقَدْ عَاذَ بِمَعَاذٍ قَالَ عُثْمَانُ رَضِيَ اللَّهُ عَنْهُ بَلَى قَالَ فَإِنِّي أَعُوذُ بِاللَّهِ أَنْ تَسْتَعْمِلَنِي فَأَعْفَاهُ وَقَالَ لَا تُخْبِرْ بِهَذَا أَحَدًا‏.‏