After the destruction of the Ad, the tribe of Thamud succeeded them in power and glory. They also fell to idol worshipping. As their material wealth increased so, too, did their evil ways while their virtue decreased. Like the people of Ad, they erected huge buildings on the plains and hewed beautiful homes out of the hills. Tyranny and oppression became prevalent as evil men ruled the land.
"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