The people of Ad lived many years in the windswept hills of an area between Yemen and Oman. They were physically well-built and renowned for their craftsmanship especially in the construction of tall buildings with lofty towers. They were outstanding among all the nations in power and wealth, which, unfortunately, made them arrogant and boastful. Their political power was held in the hand of unjust rulers, against whom no one dared to raise a voice.
They were not ignorant of the existence of Allah, nor did they refuse to worship Him. What they did refuse was to worship Allah alone. They worshiped other gods, also, including idols. This is one sin Allah does not forgive.
Related Quran Ayaaths of this Hadith.
Surah 7 : Ayah 65 Surah 7 : Ayah 51 Surah 11 : Ayah 50 Surah 11 : Ayah 53 Surah 11 : Ayah 58 Surah 11 : Ayah 60 Surah 11 : Ayah 89 Surah 23 : Ayah 32 Surah 26 : Ayah 124 Surah 46 : Ayah 24"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