It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the people of the tribes of Ri'l, Dhakwan, Usayyah and Banu Lihyan asked for help against an enemy, so the Messenger of Allah (peace and blessings be upon him) sent seventy Companions to help them. We used to call them the qurra' (reciters) of our time; they would gather firewood by day and stand in prayer by night. When they reached the place of Bi'r Ma'unah, these tribes martyred them and betrayed them. When the Prophet (peace and blessings be upon him) learned of this incident, he supplicated for a month in the Fajr prayer against some of the Arab tribes: Ri'l, Dhakwan, Usayyah and Banu Lihyan. Anas (may Allah be pleased with him) says: We used to recite Qur'an about them, then this ruling was lifted: "Convey to our people that we have met our Lord; He is pleased with us and He has made us pleased."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3094