Musnad Ahmed: Hadith 2728

The Messenger of Allah (ﷺ) prayed Qunoot every day for an entire month, at Zuhr, ‘Asr, Maghrib, 'Ishaʼand Fajr, at the end of every prayer. When he said, "Sami’ allahu liman hamidah" in the final rak'ah, he would pray against them, against a clan of Banu Sulaim, against Ri'l, Dhakwan and ‘Usayyah, and those who were behind him would say Ameen. He sent (envoys) to them, to call them to Islam, and they killed them. 'Affan said in his hadeeth: And ‘Ikrimah said: This was the beginning of Qunoot.