قَالَ يَحْيَى : سَمِعْتُ مَالِكًا، يَقُولُ : الْأَمْرُ 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، فَلَا وَصِيَّةَ لَهُ
Imam Malik, may Allah have mercy on him, said: In our view, this ruling is agreed upon that the will (wasiyyah) of a weak-minded, foolish, or insane person who sometimes regains sanity is valid, when he has enough understanding to comprehend the will he is making. If he does not have even this much understanding, then his will is not valid.