Sunan Abi Dawud

Narrated AbuHurayrah: The Prophet (ﷺ) said: Conciliation between Muslims is permissible. The narrator Ahmad added in his version: ""except the conciliation which makes lawful unlawful and unlawful lawful."" Sulayman ibn Dawud added: The Messenger of Allah (ﷺ) said: Muslims are on (i.e. stick to) their conditions