Sahih al-Bukhari, Volume 5, Book 59, Hadith 422 (USC-MSA) ⓘ

Narrated `Asim Al-Ahwal: I asked Anas bin Malik regarding Al-Qunut during the prayer. Anas replied, "Yes (Al-Qunut was said by the Prophet in the prayer)." I said, "Is it before Bowing or after Bowing?" Anas replied, "(It was said) before (Bowing)." I said, "So-and-so informed me that you told him that it was said after Bowing." Anas replied, "He was mistaken, for Allah's Messenger said Al-Qunut after Bowing for one month. The Prophet had sent some people called Al-Qurra who were seventy in number, to some pagan people who had concluded a peace treaty with Allah's Messenger. But those who had concluded the treaty with Allah's Messenger violated the treaty (and martyred all the seventy men). So Allah's Apostle said Al-Qunut after Bowing (in the prayer) for one month, invoking evil upon them.

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، حَدَّثَنَا عَاصِمٌ الأَحْوَلُ، قَالَ سَأَلْتُ أَنَسَ بْنَ مَالِكٍ ـ رضى الله عنه ـ عَنِ الْقُنُوتِ، فِي الصَّلاَةِ فَقَالَ نَعَمْ‏.‏ فَقُلْتُ كَانَ قَبْلَ الرُّكُوعِ أَوْ بَعْدَهُ قَالَ قَبْلَهُ‏.‏ قُلْتُ فَإِنَّ فُلاَنًا أَخْبَرَنِي عَنْكَ أَنَّكَ قُلْتَ بَعْدَهُ، قَالَ كَذَبَ إِنَّمَا قَنَتَ رَسُولُ اللَّهِ صلى الله عليه وسلم بَعْدَ الرُّكُوعِ شَهْرًا، أَنَّهُ كَانَ بَعَثَ نَاسًا يُقَالُ لَهُمُ الْقُرَّاءُ، وَهُمْ سَبْعُونَ رَجُلاً إِلَى نَاسٍ مِنَ الْمُشْرِكِينَ، وَبَيْنَهُمْ وَبَيْنَ رَسُولِ اللَّهِ صلى الله عليه وسلم عَهْدٌ قِبَلَهُمْ، فَظَهَرَ هَؤُلاَءِ الَّذِينَ كَانَ بَيْنَهُمْ وَبَيْنَ رَسُولِ اللَّهِ صلى الله عليه وسلم عَهْدٌ، فَقَنَتَ رَسُولُ اللَّهِ صلى الله عليه وسلم بَعْدَ الرُّكُوعِ شَهْرًا يَدْعُو عَلَيْهِمْ‏.‏