Al-Kāfi
Hadith 150 9ـ الْحُسَيْنُ بْنُ مُحَمَّدٍ عَنْ مُعَلَّى بْنِ مُحَمَّدٍ عَنِ الْحَسَنِ بْنِ عَلِيٍّ الْوَشَّاءِ عَنْ عَاصِمِ بْنِ حُمَيْدٍ عَنْ أَبِي بَصِيرٍ قَالَ سَمِعْتُ أَبَا عَبْدِ الله (عَلَيْهِ السَّلام) يَقُولُ اكْتُبُوا فَإِنَّكُمْ لا تَحْفَظُونَ حَتَّى تَكْتُبُوا.
9. Al-Husayn ibn Muhammad has narrated from Mu‘alla ibn Muhammad from al-Hassan ibn Ali al-Washsha’ from ‘Asim ibn Humayd from abu Basir who has said the following. “(Imam) abu ‘Abdallah (a.s.) said, ‘You must write down because you will not memorize until you write down.’”