Judge Abū al-Faraj said:
In this account there is such wisdom and abundant benefit that whoever gives it due attention, commits it to memory, understands it, acts upon it, disciplines his soul in accordance with it, and refines himself by constantly returning to it, will reap its full reward by pausing at its lessons. Furthermore, in the words that the Commander of the Believers relates therein from the Prophet ﷺ lies something no intelligent and knowledgeable person can afford to ignore; blessed is the one guided to receive it, and fortunate (1) is he whom Allah enables to carry it out and embrace it (2).

I say: The chain of transmission for this report, and for the hadith it contains that is traced back to the Prophet, is weak. Certain expressions in its wording exhibit a strangeness indicating that parts of it have not been soundly preserved. Allah knows best.

Al-Aṣmaʿī, al-ʿUtubī, al-Madāʾinī and others have reported that Muʿāwiyah asked al-Ḥasan ibn ʿAlī about matters of this type, and that he replied with something similar to what has been cited above, though that version is far longer. Allah knows best.

ʿAlī ibn al-ʿAbbās al-Ṭabarānī said: The signet-ring of al-Ḥasan ibn ʿAlī bore the inscription (3):

Provide for your soul, as best you can, the shield of piety—
For death, O youth, is surely closing in on you (4).
You wake in joy as though you will never see
The loved ones of your heart laid in graves, decayed.

Imām Aḥmad said: Muṭṭalib ibn Ziyād Abū Muḥammad narrated to us; Muḥammad ibn Abān narrated to us; al-Ḥasan ibn ʿAlī said to his sons and the sons of his brother (5):
“Seek knowledge! Today you are the youngsters of a people, yet tomorrow you will be their elders. Whoever among you cannot memorize should write.”

Al-Bayhaqī transmitted it from al-Ḥākim [from al-Aṣamm] (6) through ʿAbdullāh ibn Aḥmad, from his father. [In another wording: “If you are the youngsters of a people, it may well be that you will become the elders of another people.”] (7)

Muḥammad ibn Saʿd said: al-Ḥasan ibn Mūsā and Aḥmad ibn Yūnus told us, saying: Zuhayr ibn Muʿāwiyah narrated to us; Abū Isḥāq narrated to us from ʿAmr ibn al-Aṣamm, who said:
I said to al-Ḥasan ibn ʿAlī, “These partisans claim that ʿAlī will be sent back [before the Day of Resurrection].” He replied, “By Allah, they lie; those are not the true Shīʿa. Had we known that he would return, we would not have married off his wives, nor divided his estate.” (8)