Ali Ibn Al Husain used to lead a seemingly miserly life. But when he died they discovered that he was supporting one hundred poor families in Madinah. Muhammad Ibn Ishaq said: Some people of Madinah used to live not knowing where from they got their livelihood. When Ali Ibn Al Husain died they lost what used to be sent to them by night. As a matter of fact, Ali Ibn Al Husain used to carry a bag of bread by night on his back and distribute it as charity. He would say: “The secret charity puts out the anger of Allah.” When Ali Ibn Al Husain died and people washed his body, they found some black traces on his back. They said: What is this? Then the answer was that he used to carry bags of flour on it by night and would give them to the poor people of Madinah. That is why when he died, people of Madinah said: We only lost the secret charity when Ali Ibn Al Husain died.
Source: “Luminaries of Islam”