He heard the Prophet ﷺ, when he raised his head from the final rakah of the dawn prayer, say, "O Allah, curse so-and-so and so-and-so," supplicating against certain men from among the hypocrites. Then Allah revealed, "It is not for you to decide, whether He turns to them in mercy or punishes them, for indeed they are wrongdoers" [Al Imran 3:128].
أخبرنا إسحق بن إبراهيم قال أنبأنا عبد الرزاق قال حدثنا معمر عن الزهري
أنه سمع النبي ﷺ حين رفع رأسه من صلاة الصبح من الركعة الآخرة قال اللهم العن فلانا وفلانا يدعو على أناس من المنافقين فأنزل الله عز وجل {ليس لك من الأمر شيء أو يتوب عليهم أو يعذبهم فإنهم ظالمون}
Bukhari narrated it in the Book of Military Expeditions, chapter "You have no say in the matter...", hadith no. 4069 and hadith nos. 7346 and 4559, from the hadith of Mamar, and it is also in Kubra, hadith no. 665. Nasai said, "No one among the trustworthy narrators has narrated this hadith except Mamar," but this does not harm it at all.