Al-Ays ibn al-Qasim asked Imam Sadiq (a.s) how to greet the people of the Book when writing a letter. He said: “Write: “And Peace to all who follow guidance” [The Holy Quran: Ta- Ha 20:47] in the beginning, and write: “And Peace on the apostles. And Praise to God, the Lord and Cherisher of the Worlds” [The Holy Quran: Saffat 37:181-182] at the end of the letter.”