Al-Kāfi - Volume 1 > The Imams are those who have received Knowledge and it is firmly Established in their Hearts
Hadith #1

1ـ أَحْمَدُ بْنُ مِهْرَانَ عَنْ مُحَمَّدِ بْنِ عَلِيٍّ عَنْ حَمَّادِ بْنِ عِيسَى عَنِ الْحُسَيْنِ بْنِ الْمُخْتَارِ عَنْ أَبِي بَصِيرٍ قَالَ سَمِعْتُ أَبَا جَعْفَرٍ (عَلَيْهِ السَّلام) يَقُولُ فِي هَذِهِ الايَةِ بَلْ هُوَ آياتٌ بَيِّناتٌ فِي صُدُورِ الَّذِينَ أُوتُوا الْعِلْمَ فَأَوْمَأَ بِيَدِهِ إِلَى صَدْرِهِ.

1. Ahmad ibn Mahran has narrated from Muhammad ibn Ali from Hammed ibn ’Isa from al-Husayn ibn al-Mukhtar from abu Basir who has said that he heard abu ‘Abdallah (a.s.) say the following about this verse of the Holy Quran. “In fact, the Quran consists of illustrious verses that exist in the hearts of those who have knowledge. . .” (29:49) The Imams (a.s.) pointed to his own hear.”