Tafsir of Al-Qasas 28:55

"And when they hear vain talk"—this refers to idle speech. Mujahid said: "It means harm." Al-Dahhak said: "It means polytheism." Ibn Zayd said: "It means what the Jews altered of the description of the Messenger, may Allah bless him and grant him peace."

"They turn away from it"—meaning, they turn away from vain talk out of generosity, as in His, the Exalted’s, saying: "And when they pass by vain talk, they pass by with dignity."

"And they say to us, our deeds and to you your deeds"—this is a dissociation from them, as in His, the Exalted’s, saying: "For you is your religion, and for me is my religion."

"Peace be upon you"—they said this as a farewell to them, not as a greeting; or it is likewise for the purpose of dissociation, as in His, the Exalted’s, saying: "And when the ignorant address them, they say: Peace." In any case, there is no evidence in the verse for the permissibility of initiating a greeting of peace (salam) to a disbeliever, as Al-Jassas claimed; for the intent here is nothing other than dissociation or leave-taking. It is narrated from the Prophet, may Allah bless him and grant him peace, regarding the disbelievers: "Do not initiate the greeting of peace to them, and if the People of the Book greet you, say: 'And upon you.'" Yes, it is narrated from Ibn Abbas that it is permissible to say to a disbeliever, by way of initiating the greeting: "‘alayka al-salam" (peace be upon you), intending by it "Allah, the Exalted, be upon you" [as a curse], but this is weak.

"We seek not the ignorant"—this is an explanation of the motivation for the dissociation and the farewell; meaning, we do not seek the company of the ignorant, nor do we desire to associate with them.