وَحَدَّثَنِي مَالِكٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ أَبِي بَكْرِ بْنِ حَزْمٍ، أَنَّ غُلاَمًا، مِنْ غَسَّانَ حَضَرَتْهُ الْوَفَاةُ بِالْمَدِينَةِ وَوَارِثُهُ بِالشَّامِ فَذُكِرَ ذَلِكَ لِعُمَرَ بْنِ الْخَطَّابِ فَقِيلَ لَهُ إِنَّ فُلاَنًا يَمُوتُ أَفَيُوصِي قَالَ فَلْيُوصِ ‏.‏ قَالَ يَحْيَى بْنُ سَعِيدٍ قَالَ أَبُو بَكْرٍ وَكَانَ الْغُلاَمُ ابْنَ عَشْرِ سِنِينَ أَوِ اثْنَتَىْ عَشْرَةَ سَنَةً ‏.‏ قَالَ فَأَوْصَى بِبِئْرِ جُشَمٍ فَبَاعَهَا أَهْلُهَا بِثَلاَثِينَ أَلْفَ دِرْهَمٍ ‏.‏ قَالَ يَحْيَى سَمِعْتُ مَالِكًا يَقُولُ الأَمْرُ الْمُجْتَمَعُ عَلَيْهِ عِنْدَنَا أَنَّ الضَّعِيفَ فِي عَقْلِهِ وَالسَّفِيهَ وَالْمُصَابَ الَّذِي يُفِيقُ أَحْيَانًا تَجُوزُ وَصَايَاهُمْ إِذَا كَانَ مَعَهُمْ مِنْ عُقُولِهِمْ مَا يَعْرِفُونَ مَا يُوصُونَ بِهِ فَأَمَّا مَنْ لَيْسَ مَعَهُ مِنْ عَقْلِهِ مَا يَعْرِفُ بِذَلِكَ مَا يُوصِي بِهِ وَكَانَ مَغْلُوبًا عَلَى عَقْلِهِ فَلاَ وَصِيَّةَ لَهُ ‏.‏

Malik related to me from Yahya ibn Said from Abu Bakr ibn Hazmthat a boy from Ghassan was dying in Madina while his heir was inSyria. That was mentioned to Umar ibn al-Khattab. It was said to him,"So-and-so is dying. Shall he make a bequest?" He said, "Let him makea bequest." Yahya ibn Said said that Abu Bakr had said, "Hewas a boy of ten or twelve years." Yahya said, "He willed the well ofJusham, and his people sold it for 30,000 dirhams." Yahyasaid that he heard Malik say, "The generally agreed-on way of doingthings in our community is that a simpleton, an idiot, or a lunaticwho recovers at times, can make wills if they have enough of theirwits about them to recognise what they will. Someone who has notenough wits to recognise what he wills, and is overcome in hisintellect, cannot make a bequest." Translation Not Available

Book reference: Muwatta Imam Malik Book 37 Hadith 1460
Web reference: Muwatta Imam Malik Book 37 Hadith 3