According to the account of Tabari, when North Africa had been duly conquered by Abdullah b Sa'ad b Abi Sarah, two of his Generals Abdullah b Nafiah b Husain, and Abdullah b Nafi' b Abdul Qais were commissioned to invade Spain by sea. On this occasion Uthman is reported to have addressed a letter to the invading force. In the course of the letter, Uthman said:
"Constantinople will be conquered from the side of Spain. Thus if you conquer Spain you will have the honor of taking the first step towards the conquest of Constantinople. You will have your reward in this behalf both in this world and the next."
Kaab al Ahbar, an eminent companion and a counselor of Uthman is reported to have said:
"The people who conquer Spain after crossing the sea will be identified on the Doomsday on account of the special light that would radiate from them."