I shall not be pleased unless you call Messenger of Allah ﷺ as witness to what you confer as a gift on your son. (Nu'man said): So father took hold of my hand and I was at that time a boy, and came to Messenger of Allah ﷺ. and said: Messenger of Allah, the mother of this son (of mine), daughter of Rawaha wishes that I should call you witness to what I confer as gift to her son. Messenger of Allah (may pease be upon him) said: Bashir, have you any other son besides this (son of yours)? He said: Yes. He (the Holy Prophet) said: Have you given gifts to all of them like this? He said: No. Thereupon he (the Holy Prophet) said: Then call me not as witness, for I cannot be witness to an injustice. (Using translation from Muslim 1623f)
أَنَّ أُمَّهُ ابْنَةَ رَوَاحَةَ سَأَلَتْ أَبَاهُ بَعْضَ الْمَوْهِبَةِ مِنْ مَالِهِ لِابْنِهَا فَالْتَوَى بِهَا سَنَةً ثُمَّ بَدَا لَهُ فَوَهَبَهَا لَهُ فَقَالَتْ لَا أَرْضَى حَتَّى تُشْهِدَ رَسُولَ اللهِ ﷺ عَلَى مَا وَهَبْتَ لِابْنِي فَأَخَذَ أَبِي بِيَدِي وَأَنَا غُلَامٌ يَوْمَئِذٍ فَأَتَى رَسُولَ اللهِ ﷺ فَقَالَ يَا رَسُولَ اللهِ إِنَّ أُمَّ هَذَا ابْنَةَ رَوَاحَةَ قَاتَلَتْنِي مُنْذُ سَنَةٍ عَلَى بَعْضِ الْمَوْهِبَةِ مِنْ مَالِي لِابْنِي هَذَا وَقَدْ بَدَا لِي فَوَهَبْتُهَا لَهُ وَقَدْ أَعْجَبَهَا أَنْ أُشْهِدَكَ عَلَى الَّذِي وَهَبْتُ لَهُ فَقَالَ رَسُولُ اللهِ ﷺ «يَا بَشِيرُ أَلَكَ وَلَدٌ سِوَى هَذَا؟» قَالَ نَعَمْ فَقَالَ رَسُولُ اللهِ ﷺ «أَفَكُلُّهُمْ وَهَبْتَ لَهُمْ مِثْلَ الَّذِي وَهَبْتَ لِابْنِكَ هَذَا؟» قَالَ لَا قَالَ رَسُولُ اللهِ ﷺ «فَلَا تُشْهِدْنِي إِذًا فَإِنِّي لَا أَشْهَدُ عَلَى جَوْرٍ»