A couple of Scriptures on the subjects that pertain to this debate....

Gal 1:6-9 I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.
But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.

2 Cor 11:3,4 But I fear, lest by any means, as the serpent beguiled Eve through his subtlety, so your minds should be corrupted from the simplicity that is in Christ.
For if he that cometh preacheth another Jesus, whom we have not preached, or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him.

Acts 20:26-31 Wherefore I take you to record this day, that I am pure from the blood of all men. For I have not shunned to declare unto you all the counsel of God.
Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood.
For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock.
Also of your own selves shall men arise, speaking perverse things, to draw away disciples after them.
Therefore watch, and remember, that by the space of three years I ceased not to warn every one night and day with tears.

Rev 22:7 Behold, I come quickly: blessed is he that keepeth the sayings of the prophecy of this book.

Rev 22:18-20 For I testify unto every man that heareth the words of the prophecy of this book, If any man 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.
He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus.