The Messenger of Allah ﷺ said, "Whoever deliberately lies about me, let him take his seat in the Fire."
حدثنا أبو خيثمة زهير بن حرب حدثنا هشيم عن أبي الزبير
قال رسول الله ﷺ من كذب علي متعمدا فليتبوأ مقعده من النار
[Sahih, mutawatir] Ahmad reported it (3/303) from Hushaym, with the same chain, explicitly stating that he heard it directly, and the hadith is mutawatir as noted in Al-Azhar al-Mutanathirah fi al-Ahadith al-Mutawatirah and elsewhere.