From Sahih Bukhari (Hadith 1571):
Narrated `Imran:We performed Hajj-at-Tamattu` in the lifetime of Allah's Messenger (ﷺ) and then the Qur'an was revealed (regarding Hajj-at-Tamattu`) and somebody said what he wished (regarding Hajj-at-Tamattu`) according his own opinion
Reference: Bukhari 1571