عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ قَالَ ذَكَرْتُ الْمُحَدَّثَ عِنْدَ اَبِي عَبْدِ اللهِؑ قَالَ فَقَالَ اِنَّهُ يَسْمَعُ الصَّوْتَ وَ لَا يَرَى فَقُلْتُ اَصْلَحَكَ اللهُ كَيْفَ يَعْلَمُ اَنَّهُ كَلَامُ الْمَلَكِ قَالَ اِنَّهُ يُعْطَى السَّكِينَةَ وَ الْوَقَارَ حَتَّى يَعْلَمَ اَنَّهُ مَلَكٌ
Muhammad Ibn Muslim says, “I mentioned (i.e. inquired about) a muhaddath in front of Imam Abu Abdillah (al-Sadeq a.s.).”
He (peace be upon him) replied, “Surely, he (the muhaddath) hears the sound but does not see (the angel).”
I asked, “May Allah reform (your conditions)! How does he know that it is the talk of the angel?”
He (peace be upon him) informed, “Verily, he is granted calmness and dignity till he knows that it is an angel.”
1) Not seeing the angel by a muhaddath applies for the fallible believers (like Salman, Abuzar, etc. as is clear from the previous tradition) and not for the infallible Imams (peace be upon them). For, even the children of the infallible Imams (peace be upon them) could see the angels and converse with them.
2) In this narration, Imam (peace be upon him) clarifies the signs of a true and divine inspiration. Another sign is that it is always in conformity with the Shariah and divine teachings. For example, al-Hasan al-Basri heard a voice during the battle of Jamal. Ameerul Momineen (peace be upon him) warned him that it was the voice of the Satan.
1. Behaar al-Anwaar, vol. 26, p. 68, H. 7
2. Basaaer al-Darajaat, p. 323, H. 9, Chapter 6