Uthman remained the Caliph for twelve years. During these twelve years, Uthman presided at the Hajj ceremonies personally for ten years. He could not perform the pilgrimage during the first year of his caliphate, as he was suffering from the oozing of blood from the nose. That year Abdur Rahman b Auf led the Muslims in Hajj on behalf of Uthman. Uthman could not perform the pilgrimage during the last year of his life, as he was besieged in his house by the rebels. On that occasion, Uthman appointed Abdullah b Abbas as the "Amir-ul-Hajj".
"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