It is narrated from Hazrat Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) recited Qunoot Nazilah after the bowing (ruku) in the Fajr prayer for a month, and he continued to invoke curses upon the tribes of Ri'l, Dhakwan, 'Usayyah, and Banu Lihyan, who had disobeyed Allah and His Messenger.