1. Muhammad ibn al-Hassan has narrated from Ali ibn Muhammad from Sahl ibn Ziyad from Muhammad ibn ‘Isa from ‘Ubaudallah al-Dihqan from Durust al-Wasiti from Ibrahim ibn ‘Abd al-Hamid from abu al-Hassan Musa (a.s.) who has said the following. “Once the Holy Prophet (s.a) entered the Mosque and found a group of people gathered around a man. He asked, “who is he?” It was said that he was a ‘allamah. He then asked them, “What is that? “ They replied that he is the most learned man about the genealogy, the chronology, and the history of the pre-Islamic days of darkness and the poetry of Arabs. The Imam said, ‘The holy Prophet (s.a.) then told them. “Knowledge consists of only three kinds: A strong sign, a justly enjoined obligation or an established tradition. Other then these are of the extra achievements.”’
