Surah 28

Surah 28:52

"Those to whom We gave the Book before it – they believe in it."

Those to whom We gave the Book before it – they believe in it
This and the following verse indicate a scenario in which the People of the Book – presumably Jews and/or Christians – believe in the recitations of the messenger. They describe themselves as Muslims (v. 53). Are these “believers” converts to Islam?

- from The Quran with Christian Commentary: A Guide to Understanding the Scripture of Islam