Jami` at-Tirmidhi 2640
جامع الترمذي#2640SahihNarrated Abu Hurairah:that the Messenger of Allah (ﷺ) said: "The Jews split into seventy-one sects, or seventy-two sects, and the Christians similarly, and my Ummah will split into seventy-three sects
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirHasan Sahih
Al-AlbaniHasan Sahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiIsnaad Hasan
In-book reference: 40:35