Sahih al-Bukhari 2642

Sulayman ibn Harb narrated to us: Hammad ibn Zayd narrated to us, from Thabit, from Anas, may Allah be pleased with him, who said: A funeral passed by the Prophet ﷺ and they spoke well of the deceased. He said: “It has been confirmed.” Then another passed by, and they spoke ill of its deceased—or said something else—and he said: “It has been confirmed.” They said: “Messenger of Allah, you said ‘It has been confirmed’ for this one and for that one?” He said: “The people’s testimony; the believers are Allah’s witnesses on earth.”