Al-Kāfi

Hadith 800
imam-kazimahl-al-baytwilayah
4ـ أَحْمَدُ بْنُ مِهْرَانَ عَنْ مُحَمَّدِ بْنِ عَلِيٍّ عَنْ مُوسَى الصَّيْقَلِ عَنِ الْمُفَضَّلِ بْنِ عُمَرَ قَالَ كُنْتُ عِنْدَ أَبِي عَبْدِ الله (عَلَيْهِ السَّلام) فَدَخَلَ أَبُو إِبْرَاهِيمَ (عَلَيْهِ السَّلام) وَهُوَ غُلامٌ فَقَالَ اسْتَوْصِ بِهِ وَضَعْ أَمْرَهُ عِنْدَ مِنْ تَثِقُ بِهِ مِنْ أَصْحَابِكَ.
4. Ahmad ibn Mihran has narrated from Muhammad ibn Ali from Musa as.-Sayqal from al-Mufaddal ibn ‘Umar who has said the following. “Once I was in the presence of abu ‘Abdallah (a.s.) that abu Ibrahim came and was a young boy. He (abu ‘Abdallah ) said (to me), “Accept my directive will about him (Musa ibn Ja‘far) and discuss his task (Leadership with Divine Authority) with your reliable companions.” :
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī