Sahih al-Bukhari, Volume 5, Book 59, Hadith 415 (USC-MSA) ⓘ
Narrated Anas: Allah's Messenger said Al-Qunut for one month after the posture of Bowing, invoking evil upon some 'Arab tribes.
حَدَّثَنَا مُسْلِمٌ، حَدَّثَنَا هِشَامٌ، حَدَّثَنَا قَتَادَةُ، عَنْ أَنَسٍ، قَالَ قَنَتَ رَسُولُ اللَّهِ صلى الله عليه وسلم شَهْرًا بَعْدَ الرُّكُوعِ يَدْعُو عَلَى أَحْيَاءٍ مِنَ الْعَرَبِ.
also referenced under: Book 64, Hadith 133 (In-Book) & Hadith 4089 (DarusSalam)