Narrated Al-Bara' bin 'Azib (RA): The Prophet ( صلی اللہ علیہ وسلم ) sent 'Ali to Yemen. The narrator mentioned the complete Hadith. He said, "Ali sent a letter regarding their (the people of Yemen) acceptance of Islam. When Allah's Messenger ( صلی اللہ علیہ وسلم ) read the letter, he prostrated in gratitude to Allah the Most High for that." [Reported by al-Baihaqi] . And its basic meaning is found in Sahih al-Bukhari.