Sahih al-Bukhari 2801

It is related that Anas said, "The Prophet, may Allah bless him and grant him peace, sent some seventy men from the Banu Sulaym to the Banu 'Amir. When they arrived, my uncle said to them, 'I will go ahead of you. If they grant me security so that I can convey the message of the Messenger of Allah, may Allah bless him and grant him peace, (that will be fine.) Otherwise you will be near me.' He went forward and they gave him security. While he was conveying to them the message of the Prophet, may Allah bless him and grant him peace, they made a gesture to one of their men and he attacked him and stabbed him through. He said, 'Allah is greater! By the Lord of the Ka'ba, I have won!' Then they attacked the rest of his companions and killed them except for a lame man who climbed the mountain. (Hammam said, "I think there was another man with him.") Jibril, peace be upon him, informed the Prophet, may Allah bless him and grant him peace, that they had met their Lord and He was pleased with them and they were pleased with Him. We used to recite, 'Convey to our people that we have met our Lord and He is pleased with us and We are pleased' until it was abrogated later. He cursed them for forty mornings - Ri'l, Dhakwan, Banu Lihyan and Banu 'Usayya who disobeyed Allah and His Messenger." [These were the Ansar who were sent to teach the Qur'an and call the people of Najd to Islam. This took place at Bi'r Ma'una. The cursing took place in the qunut in the Fajr prayer.]