سورة الدخان

The Messenger of Allah (peace be upon him and his family): Do not revile "Tubba" [one of the kings of Yemen whose name, according to some narrations, was "As'ad Abu Karib"], for he had accepted Islam.

Imam Sadiq (peace be upon him): "Tubba" addressed the Aws and the Khazraj (the two important tribes of Madinah) and said: "You remain here (in Madinah) until the Prophet of the End Times (peace be upon him and his family) rises; as for me, had I reached [the time of] him, I would have girded myself in his service and risen alongside him."

Imam Ali (peace be upon him): A man from Sham asked the Commander of the Faithful (peace be upon him): "Why was Tubba called Tubba?" The Imam said: "Because he was a slave who was a scribe, and he used to write for a king who ruled before him. Whenever he wrote a letter, [at its beginning] he would write: In the name of the Allah who created that upon which the sun shines and upon which the wind blows. That king said: Begin the letter in the name of the king of thunder (which was his own name). He said: I begin only in the name of my Lord, and then I shall attend to your request. Allah the Mighty and Majestic appreciated this from that slave and gave him the kingdom of that sultan, and the people followed and obeyed him; and so he became known as 'Tubba' [the followed one]."