Musannaf Ibn Abi Shayba 3:6397

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Yunus, from al-Hasan, who said: When the delegation of Thaqif came to the Prophet, may Allah bless him and grant him peace, they stayed in a tent that was in the back of the mosque. When the time for prayer arrived, a man from the people said: "O Messenger of Allah, the time for prayer has arrived, and these are a disbelieving people, and they are in the mosque." The Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, the earth does not become impure," or something similar to this.