Imam Sadiq (peace be upon him) said: The fourth Imam (peace be upon him) wept for his father for around forty years, the days of which he used to remain in a state of fasting while the nights he would pass in worship. When it would be time for breaking the fast, his slave would bring food and water, and placing them before him, say: “Eat it”. (Whereupon) he (peace be upon him) would say: “My father was killed in a state of hunger and thirst”, and then he would weep so intensely that his food would become moistened by his tears. And this continued for as long as he was alive.
One of the friends of Imam Sajjaad (peace be upon him) says:
One day the Imam (peace be upon him) had started out for the desert and so I too went after him. When I found him, I saw him prostrating upon a rough stone, weeping and wailing and counted that he recited a dhikr a thousand times. He then raised his head (and I observed) that his face and beard were moistened with tears.
I said to him: O’ My Master! End your sorrow and reduce your weeping! He said: Woe unto you! Ya’qub, the son of Ishaaq, was a prophet and the son of a prophet. He had twelve sons and when one of them was lost, he was so grieved that his hair turned white, his body bent over and due to the intense weeping his eyes lost their vision, and this despite the fact that his son was still alive. But I have seen my father, brother and seventeen persons from my family being killed and lying on the ground with my own eyes, so how can my sorrow end and how can the tears of my eyes reduce?( Namunah-e-Ma’arif, vol. 2, pg. 589; Anwaar al-Nu’maaniyyah, pg. 2, pg. 27 )
Reference -Anecdotes for Reflection Part 4