Al-Kāfi - Volume 7 > The Matters for which one can Make a Will and what is Preferable in the Issue
Hadith #6

6- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ هِشَامِ بْنِ سَالِمٍ وَحَفْصِ بْنِ الْبَخْتَرِيِّ وَحَمَّادِ بْنِ عُثْمَانَ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ مَنْ أَوْصَى بِالثُّلُثِ فَلَمْ يَتَّرِكْ.

6. Ali ibn Ibrahim has narrated from his father from ibn abu ‘Umayr from Hisham ibn Salim and Hafs ibn al-Bakhtariy and Hammad ibn ‘Uthaman who has narrated the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said, ‘If one makes a will about one-third has not left any legacy.’”