The Quran is a record of the exact words revealed by God through the Angel Gabriel to the Prophet Muhammad (SAW). It was memorized by Muhammad (SAW) and then dictated to his Companions, and written down by scribes, who cross-checked it during his lifetime. Not one word of its 114 chapters, Suras, has been changed over the centuries, so that the Quran is in every detail the unique and miraculous text which was revealed to Muhammad (SAW) fourteen centuries ago.
"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