Sunan an-Nasa'i, Volume 4, Book 31, Hadith 3712 (DarusSalam) ⓘ

It was narrated that An-Nu'man said: "My mother asked my father for a gift and he gave it to me. She said: 'I will not be contented until you ask the Messenger of Allah to bear witness.' So my father took me by the hand, as I was still a boy, and went to the Messenger of Allah. He said: 'O Messenger of Allah, the mother of this boy, the daughter of Rawahah, asked me for a gift, and she wanted me to ask you to bear witness to that.' He said: 'O Bashir, do you have any other child apart from this one?' He said: 'Yes.' He said: 'Have you given him gifts like that which you have given to this one?' He said: 'No.' He said: 'Then do not ask me to bear witness, for I will not bear witness to unfairness.'"

أَخْبَرَنَا أَبُو دَاوُدَ، قَالَ حَدَّثَنَا يَعْلَى، قَالَ حَدَّثَنَا أَبُو حَيَّانَ، عَنِ الشَّعْبِيِّ، عَنِ النُّعْمَانِ، قَالَ سَأَلَتْ أُمِّي أَبِي بَعْضَ الْمَوْهِبَةِ فَوَهَبَهَا لِي فَقَالَتْ لاَ أَرْضَى حَتَّى أُشْهِدَ رَسُولَ اللَّهِ صلى الله عليه وسلم ‏.‏ قَالَ فَأَخَذَ أَبِي بِيَدِي وَأَنَا غُلاَمٌ فَأَتَى رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أُمَّ هَذَا ابْنَةَ رَوَاحَةَ طَلَبَتْ مِنِّي بَعْضَ الْمَوْهِبَةِ وَقَدْ أَعْجَبَهَا أَنْ أُشْهِدَكَ عَلَى ذَلِكَ ‏.‏ قَالَ ‏"‏ يَا بَشِيرُ أَلَكَ ابْنٌ غَيْرُ هَذَا ‏"‏ ‏.‏ قَالَ نَعَمْ ‏.‏ قَالَ ‏"‏ فَوَهَبْتَ لَهُ مِثْلَ مَا وَهَبْتَ لِهَذَا ‏"‏ ‏.‏ قَالَ لاَ ‏.‏ قَالَ ‏"‏ فَلاَ تُشْهِدْنِي إِذًا فَإِنِّي لاَ أَشْهَدُ عَلَى جَوْرٍ ‏"‏ ‏.‏