Jami` at-Tirmidhi 1901
جامع الترمذي#1901SahihAbdur-Rahman bin Abi Bakrah narrated from his father who said:" The messenger of Allah said: 'Shall I not tell you of the biggest of the major sins?' they said : 'Of course! O Messenger of Allah!' He said: 'To join partners with Allah, and disobeying one's parents.'"He said : " He sat up, and he had been reclining. He said: 'And false testimony, or false speech.' And the Messenger of Allah would not stop saying it until we said (to ourselves): 'I wish that he would stop
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 27:5