Sahih Muslim 679 b
The Book of Mosques and Places of Prayer
It is recommended to say qunut in all prayers if a calamity befalls the Muslims – and refuge is sought from Allah (regarding that). It is recommended to say qunut in Subh at all times. And the clarification that it is to be said after raising the head from bowing in the final rak`ah, and it is recommended to say it out loud
Khufaf b. Ima' reported that the Messenger of Allah (ﷺ), bowed (in prayer) and then lifted his head and then said: So far as the tribe of Ghifar is concerned, Allah had pardoned it, and Allah had granted protection to the tribe of Aslam, and as for the tribe of Usayya, It had disobeyed Allah and His Messenger, (and further said): O Allah! curse the tribe of Lihyan curse Ri'l, and Dhakwan, and then fell in prostration. It is after this that the cursing of the unbelievers got a sanction.