Ali was the most learned man of the age in Islamic law. He acted as a Judge during the time of the Holy Prophet, and the Caliphs Abu Bakr and Umar. Some of the judgements delivered by Ali are on record, and show his highly developed sense of discerning the truth, and doing justice.
"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