Ali exhorted that while living in the world, one should not renounce the world, yet he should not have an undue attachment for the world. Detachment from the world is the means of attaining God. It is related that some one begged Ali to give him a precept. Ali said: "Do not let your wives and children be a cause of concern for you, for if they are the friends of God, He will look after His friends, and if they are the enemies of God, why should you take care of God's enemies?"
"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