What did the Prophet Muhammad (peace be upon him) do after hearing the tribes of Ril, Dhakwan, 'Usiya and Bani Lihyan had embraced Islam?
      Narrated Anas:                          The people of the tribes of Ril, Dhakwan, 'Usiya and Bani Lihyan came      to the Prophet and claimed that they had embraced Islam, and they      requested him to support them with some men to fight their own people.     The Prophet supported them with seventy men from the Ansar whom we      used to call Al-Qurra'(i.e. Scholars) who (out of piety) used to cut      wood during the day and pray all the night. So, those people took the      (seventy) men till they reached a place called Bi'r-Ma'ana where they      betrayed and martyred them. So, the Prophet invoked evil on the tribe      of Ril, Dhakwan and Bani Lihyan for one month in the prayer.     Narrated Qatada: Anas told us that they (i.e. Muslims) used to recite      a Quranic Verse concerning those martyrs which was:-- "O Allah! Let      our people be informed on our behalf that we have met our Lord Who has     got pleased with us and made us pleased." Then the Verse was      cancelled.