Musannaf Ibn Abi Shaybah

Hasan narrates that when the delegation of Banu Thaqif came to the presence of the Messenger of Allah (peace and blessings be upon him), they were accommodated in the rear part of the mosque. When the time for prayer arrived, a man said, "O Messenger of Allah! The time for prayer has come and these disbelievers are in the mosque." The Messenger of Allah (peace and blessings be upon him) said, "Nothing makes the earth impure."

Hasan narrates that the delegation of Banu Thaqif came to the service of the Prophet (peace be upon him) as a group. At that time, he was in the mosque. Someone said to him, "O Messenger of Allah! They are polytheists." He replied, "Nothing makes the earth impure."

Hazrat Abu Abdullah Asqalani says that a man told me that he saw Ibn Muhairiz shaking hands with a Christian in the mosque of Damascus.

Hazrat Mujahid did not see any harm in the People of the Book sitting in the mosque.

Hazrat Husain narrates that Hazrat Umar bin Abdul Aziz wrote a letter to his governors stating that you should not seat the judge in the mosque where Jews and Christians come to him.

Hazrat Abu Salih says that polytheists may enter the mosque only in a state of fear.