Verse 23 of Sura 42 reads {42:23}: "Say O Muhammad to mankind: I do not ask of you any reward for it, but love for relatives, and whosoever earns good".
According to traditions when the Holy Prophet was asked as to who were the relatives alluded to in the verse, the Holy Prophet said, "Verily, the reference is to Ali, Fatima, Hassan and Husain".
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari