مَرْوَانَ بْنِ مُسْلِمٍ عَنْ اَبِي عَبْدِ اللهِؑ قَالَ الْاِمَامُ عَلَمٌ بَيْنَ اللهِ عَزَّ وَ جَلَّ وَ بَيْنَ خَلْقِهِ فَمَنْ عَرَفَهُ كَانَ مُؤْمِناً وَ مَنْ اَنْكَرَهُ كَانَ كَافِراً
Marwan Ibn Muslim narrates from Imam Abu Abdillah al-Sadeq (peace be upon him), “An Imam is a standard between Allah – Mighty and Majestic be He – and His creatures. Whoever recognizes him is a believer and whoever denies him is a disbeliever.”
Note:
Allah has created man and made a religion for him. But without a divine Imam, this religion cannot be followed. Just as one cannot get proper treatment without a proper doctor and a house cannot be built without a proper engineer. One who recognizes him is a believer is quite logical because a person who is a patient, if he does not go to a qualified doctor, his sickness will become worse. If he goes to a qualified doctor, he will get proper treatment and will be cured of his illness. The same applies for the role of engineers and architects in building of houses.
References:
1. Behaar al-Anwaar, vol. 23, p. 88, H. 32
2. Kamaal al-Deen