He was the most learned man of his age. He was a living encyclopaedia of knowledge and learning. After the Holy Prophet he was the most eloquent person of the age. Because of his knowledge and wisdom he is known as the "Second Solomon". His wise sayings and aphorisms have attained the status of classical proverbs. He was the first person to write a grammar of the Arabic language. Among the early Muslims he is the only person whose collections of writings have come down to us under the title of Nahj-ul-Balagha. He was a distinguished poet. He enjoys fame as the "Father of Rhetoric". He was an authority on Mathematics. He was a master of the science of Physics. He had deep medical knowledge. After the Holy Prophet he is regarded as the greatest philosopher of Islam. He was a calligrapher and wrote a beautiful hand.
"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