Hasan (may Allah have mercy on him) said: By Allah! If all those in the heavens and the earth were to agree upon the killing of a believer, Allah the Mighty and Majestic would admit them all into Hell.
Hadith Referenceسنن سعید بن منصور / كتاب التفسير / 672
Hadith Gradingمحدثین:سنده ضعيف لضعف حماد وعباد قبل حفظهما، لكنه حسن لغيره مرفوعًا بمجموع طرقه.