Narrated Jabir:

Bashir's wife said (to her husband): Give my son your slave, and call the Messenger of Allah (ﷺ) as witness for me. So he came to the Messenger of Allah (ﷺ) and said: The daughter of so-and-so has asked me to give her som my slave and said to me: Call the Messenger of Allah (ﷺ) as witness for her. He asked: Has he brothers? He replied: Yes. He again asked: Has he given them all the same as you have given him? He replied: No. He said: This is not good, and I will be a witness to what it right.

حَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا يَحْيَى بْنُ آدَمَ، حَدَّثَنَا زُهَيْرٌ، عَنْ أَبِي 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 غُلاَمًا وَقَالَتْ لِي أَشْهِدْ رَسُولَ اللَّهِ صلى الله عليه وسلم ‏.‏ فَقَالَ ‏"‏ لَهُ إِخْوَةٌ ‏"‏ ‏.‏ فَقَالَ نَعَمْ ‏.‏ قَالَ ‏"‏ فَكُلَّهُمْ أَعْطَيْتَ مِثْلَ مَا أَعْطَيْتَهُ ‏"‏ ‏.‏ قَالَ لاَ ‏.‏ قَالَ ‏"‏ فَلَيْسَ يَصْلُحُ هَذَا وَإِنِّي لاَ أَشْهَدُ إِلاَّ عَلَى حَقٍّ ‏"‏ ‏.‏