Keep the company of the virtuous. Refrain from the company of the wicked. To oppress the weak is the worst tyranny. When softness becomes hardness, hardness becomes softness. Sometimes cure becomes malady and malady becomes cure. Sometimes an evil wisher does what is good for you, and a well wisher does what is harmful to you. Do not bank on false hopes for that is the capital of the dead. Intelligence is the application of experience. The best experience is that which bears a lesson. Avail of the opportunity before it turns against you.
"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