Ali instructed that his burial place should remain a secret. He had many enemies, and he feared lest his body might be subjected to some indignity. According to legend, the dead body of Ali was placed on a camel which was driven from Kufa. The camel stopped a few miles west of Kufa, and here the dead body of Ali was buried secretly. No tomb was raised, and nobody knew of the burial place except a few trusted persons. It is narrated that more than a hundred years later, the Abbasid Caliph, Harun-ur Rashid, went deer hunting outside Kufa, and the deer sought sanctuary at a place where the hounds would not pursue it. On inquiry as to why the place was a sanctuary, Harun-ur-Rashid was told that it was the burial place of Ali. Harun-ur Rashid ordered a mausoleum to be built on the spot. In due course, the town of Najaf grew around the mausoleum.
"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