Mishkat al-Masabih 3031
Jabir told that Bashir’s wife asked her husband* to give her son his slave and call God's Messenger as witness for her. He went to him and said, "The daughter of so and so has asked me to give her son my slave and said that I must call God’s Messenger as witness for her.” He asked whether the boy had brothers, and when he replied that he had, he asked whether he had given them all the same as he had given him. On being told that he had not, he said, "This is not good, and I will be a witness only for what is right.” 
* The literal translation is "Bashir's wife said:
Give my son your slave.” This was presumably said to her husband.

Muslim transmitted it.
عَنْ جَابِرٍ قَالَ: قَالَتِ امْرَأَةُ بَشِيرٍ: انْحَلِ ابْنِي غُلَامَكَ وَأَشْهِدْ لِي رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَأَتَى رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ: إِنَّ ابْنَةَ فُلَانٍ سَأَلَتْنِي أَنْ أَنْحَلَ ابْنَهَا غُلَامِي وَقَالَتْ: أَشْهِدْ لِي رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ: «أَلَهُ إِخْوَةٌ؟» قَالَ: نَعَمْ قَالَ: «أَفَكُلَّهُمْ أَعْطَيْتَهُمْ مِثْلَ مَا أَعْطَيْتَهُ؟» قَالَ: لَا قَالَ: «فَلَيْسَ يَصْلُحُ هَذَا وَإِنِّي لَا أَشْهَدُ إِلَّا على حق» . رَوَاهُ مُسلم