Asim reported,

I asked Anas, may Allah be pleased with him, about the qunut. He replied, "It is before the bowing."I said, "But so-and-so claims that you said it is after the bowing."He said, "He has lied."Then he narrated to us from the Prophet ﷺ that he performed the qunut for a month after the bowing, supplicating against some clans of Banu Sulaym. He said, "The Prophet ﷺ sent forty," or "seventy," the narrator was uncertain, "of the reciters to a group of the polytheists. These people intercepted them and killed them, even though there was a covenant between them and the Prophet ﷺ. I never saw him grieve over anyone as deeply as he grieved over them."

Azami 7995

Sahih

عن عاصم قال

سألت أنسارضي ٱلله عنه عن القنوت قال: قبل الركوع فقلت: إن فلانا يزعم أنك قلت بعد الركوع. فقال: كذب، ثم حدثنا عن النبي ﷺ أنه قنت شهرا بعد الركوع، يدعو على أحياء من بني سليم، قال: بعث أربعين- أو سبعين يشك فيه- من القراء إلى أناس من المشركين، فعرض لهم هؤلاء، فقتلوهم، وكان بينهم وبين النبي ﷺ عهد، فما رأيته وجد على أحد ما وجد عليهم.

الأعظمي 7995صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Jihad
Chapter
Treaty with the enemy
Section
Punishing those among the disbelievers who broke the covenant
Numbering
Jami al-Kamil 7995 (2nd edition)
Azami 7995