Hazrat Abu Abdullah Al-Asqalani says that the person who saw Hazrat Ibn Muhairiz informed me that he shook hands with a Christian in the mosque of Damascus.

Hazrat Ash'ath narrates that Hasan Basri considered it undesirable for a Muslim to shake hands with a Jew or a Christian.

Hazrat Ash'ath narrates that Hasan said: Indeed, the polytheists are impure; do not shake hands with them. Whoever shakes hands with them should perform ablution.

Hazrat Abdul Malik states that I asked Hazrat Ata about shaking hands with a Magian (Zoroastrian)? He considered it disliked (makruh).