Al-Matalib al-'Aliyah 4448 — The killing of Ali

Ja'far bin Muhammad (may Allah have mercy on him) narrates from his father, and he from Ali bin al-Husayn (may Allah have mercy on him), that when Sayyiduna Ali (may Allah be pleased with him) was martyred, Sayyiduna al-Hasan bin Ali (may Allah be pleased with them both) stood up to deliver a sermon. He praised and extolled Allah, the Blessed and Exalted, and then said: "Amma ba'd (to proceed): By Allah, tonight you have martyred a great man who (departed to his true Creator) on a night in which the Qur'an was revealed, on which Sayyiduna Isa bin Maryam (peace be upon him) was raised up (to the heavens), and on which Yusha' bin Nun (peace be upon him), the special companion and faithful attendant of Sayyiduna Musa (peace be upon him), was killed."
Imam Abu Ya'la narrated it in his Musnad. Its chain contains the narrator Sukayn bin Abd al-Aziz, who is da'if (weak), but it has supporting reports in Musnad Ahmad and other books of hadith which strengthen it.