Uthman withdrew the restriction of naval warfare. He permitted Muawiyah to invade the island of Cypress. The island was captured by the Muslims. 'The success of the Cypress campaign set the stage for the undertaking of naval activities by the Government of Egypt as well. Abdullah b Sa'ad built a strong navy. He proved to be a good naval commander, and under him the Muslims won a number of naval victories.
The first naval clash between the Byzantine navy, and the Egyptian navy took place on the Egyptian coast in 651 C.E. In this naval action, the Byzantines who were the aggressors were repulsed with a heavy loss.
"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