Al-Kāfi

Hadith 666
twelve-imams
3ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ عِمْرَانَ بْنِ مُوسَى عَنْ مُوسَى بْنِ جَعْفَرٍ عَنْ عَمْرِو بْنِ سَعِيدٍ الْمَدَائِنِيِّ عَنْ أَبِي عُبَيْدَةَ الْمَدَائِنِيِّ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلام) قَالَ إِذَا أَرَادَ الامَامُ أَنْ يَعْلَمَ شَيْئاً أَعْلَمَهُ الله ذَلِكَ.
3. Muhammad ibn Yahya has narrated from ‘Umrah ibn Musa from Musa ibn Ja‘far from ‘Amr ibn Sa‘id al-Mada’ini from abu ‘Ubayda al-Mada’ini from abu ‘Abdallah (a.s.) who has said the following. “When the Imam (a.s.) would will to know something Allah will grant him such knowledge.”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī