In a strict sense, no child of God can lose his salvation (John 10:28). But someone can acquire a sterling public reputation as being a bona fide Christian, yet ultimately be exposed as being a fraud. In the present passage the Lord makes plain that a refusal to bow before the authority of the Word of God is reason to suspect the genuineness of one’s faith.
19 and if anyone takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book.