Sahih Muslim 1624
Jabir (Allah be pleased with him) reported that the wife of Bashir said (to her husband):
Give to my son your slave as a gift, and make for me Allah's Messenger (ﷺ) a witness He came to Allah's Messenger (ﷺ) and said: The daughter of so and so (his wife Amra bint Rawaha) asked me to give my slave as a gift to her son, and call for me Allah's Messenger (ﷺ) as a witness. Thereupon he (the Holy Prophet) said: Has he (Nu'man) brothers? He (Bashir) said: Yes. He (further) said: Have you given to all others as you have given to him? He said: No. He said: Then it is not fair; and verily I cannot bear witness but only to what is just.
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدِ اللَّهِ بْنِ يُونُسَ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا أَبُو الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ قَالَتِ امْرَأَةُ بَشِيرٍ انْحَلِ ابْنِي غُلاَمَكَ وَأَشْهِدْ لِي رَسُولَ اللَّهِ صلى الله عليه وسلم ‏.‏ فَأَتَى رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ إِنَّ ابْنَةَ فُلاَنٍ سَأَلَتْنِي أَنْ أَنْحَلَ ابْنَهَا غُلاَمِي وَقَالَتْ أَشْهِدْ لِي رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ أَلَهُ إِخْوَةٌ ‏"‏ ‏.‏ قَالَ نَعَمْ ‏.‏ قَالَ ‏"‏ أَفَكُلَّهُمْ أَعْطَيْتَ مِثْلَ مَا أَعْطَيْتَهُ ‏"‏ ‏.‏ قَالَ لاَ ‏.‏ قَالَ ‏"‏ فَلَيْسَ يَصْلُحُ هَذَا ‏.‏ وَإِنِّي لاَ أَشْهَدُ إِلاَّ عَلَى حَقٍّ ‏"‏ ‏.‏