At the very end of Holy Scripture God in His providence determined that the apostle John warns his readers in the following way,
“For I testify unto every man that heareth the words of the prophecy of this book, If any shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book.”Revelation 22:18-19
Taken from a covenantal perspective the whole passage above falls on the curses side of blessings and curses. The whole of Scripture ends with this curse upon those who add or subtract from the Scriptures. And to whom is John writing his Apocalypse? The seven churches. John is not warning those wily atheists or stoics about adding or subtracting to the next. No, he is warning the church. There are two verses which remain [vss. 20-21]. 20 says that Jesus is coming back quickly which does not bode well for those who add or subtract from Scripture and in 21 John requests that the “grace of our Lord Jesus Christ be with you all.” Indeed, among other things, the grace not to corrupt the text of Scripture.
So why the warning? Taken from the penman’s perspective, John’s perspective, he sees the need to warn because he anticipates a real danger. From the Author’s perspective, the Holy Spirit’s perspective, God commands to our weaknesses. He knows that humanity is prone to take things that are not ours and desire things that are not ours. He knows that we easily fall into idolatry, blasphemy, adultery, and murder. In like manner, God knows that we are prone to meddle with God’s words. Still, God knows our hearts, but John does not.
So again, why the warning particularly from John’s side of the equation? It stands to reason that John warns not to tamper with the word of God because he has either witnessed this tampering himself in his own books or has heard of it from reputable sources. Which is to say, the Bible has been under siege by those within and without the church. For John, his greatest concern though is not toward those outside the church, but toward those within it. John is primarily concerned with God’s people tampering with God’s word; thus, he warns the seven churches not to do so under pain of plagues and damnation.
John’s warning remains in force today. How are we to know that this or that is tampering of the Scripture? Textual evidence? No. Educated opinions? No. The only way we can know is by the leading of the Spirit of God through the word of God to the people of God by faith. There is a place for textual evidence and educated opinions on this topic and that place is the place of the handmaid and nothing more. The Lord and Lady of the textual process lies with the people of God by faith reading the word of God and hearing the voice of God in those inspired words. In this way and only this way we can have a standard sacred text. All other methods lead to confusion.