Imam Sadiq (a.s.) informed: Ali b. Husain al-Sajjad (a.s.) cried over Husain (a.s.) for twenty of forty years. He (a.s.) cried whenever he wanted to eat or drink until his servant told him – O son of Allah’s Prophet! May I be your ransom! I fear that you may perish! Al-Sajjad (a.s.) replied – I shall take my sorrow and complaint to Allah. I know what you do not know. Whenever I remember the martyrdom of the children of Fatima (s.a.) I cry.
Al-Khesaal chap 5 trad 15