He says to you...

He says to you: Ali is in the same position with respect to you as Aaron (Harun) was to Moses (Musa) except that there is no prophet after you.’ Therefore, name this (grand) son of yours by the name of Harun’s son.’ So the Prophet (a.s.) said: ‘What was the name of Harun’s son, O Gabriel? ‘Shibr,’ replied Gabriel. ‘Most surely, my language is Arabic,’ retorted the Prophet. ‘Name it al-Hasan,’ explained Gabriel.

Accordingly, the Prophet (a.s.) did that.’” A narration similar to this has been reported by al-‘Amili, may Allah have mercy on him, in his book A‘yan al-Shi‘a. In the books Usd al-Ghaba and Tarikh al-Khamees, vol. 1, p. 470, it has been mentioned that the name al-Hasan was not known in the pre-Islamic period. In the book Tarikh al-Khamees it has been mentioned that Allah’s Apostle (a.s.) gave it this name after the seventh day of its birth.