He participated in all the wars of early Islam fought under the command of the Holy Prophet. In all the battles, Ali was the flag bearer of the forces of the Muslims. He was the bravest man among the Muslims. For his unusual bravery he won such titles as "Asad Allah," the lion of God, or "Haidar e Karrar" the warrior whom nobody could match. During his lifetime he killed over a thousand persons of the enemy. In the Battle of Badr alone he killed two dozen persons. He fought over a hundred duels, and in all the duels his adversaries, however strong, were killed. He was the Conqueror of Khyber.
"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