Hebrews 1:1 In the past God spoke to our forefathers through the prophets at many times and in various ways, 2 but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe.

Jude 3 Dear friends, although I was very eager to write to you about the salvation we share, I felt I had to write and urge you to contend for the faith that was once for all entrusted to the saints.

Revelation 22

18I warn everyone who hears the words of the prophecy of this book: If anyone adds anything to them, God will add to him the plagues described in this book. 19And if anyone takes words away from this book of prophecy, God will take away from him his share in the tree of life and in the holy city, which are described in this book.

True Followers of God believe that special revelation ended with the New Testament. And, that any so-called special revelations that came after the New Testament like the koran, book of mormon, unranta book, gospel of levi, book of the lamb, etc., are automatically false revelations because Jesus is God's final revelation which is recorded in the New Testament.