AMEN, AND AMEN!
Rev 22:18-21 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. The grace of our Lord Jesus Christ be with you all. Amen.
The deity making this testimony is referred to here as "I." Since it is Jesus speaking directly to John beginning in verse 12 and 13, it is natural to assume that it is our Savior speaking to John in this final passage of the Revelation letter, as well as the completion of the Holy Spirit-inspired New Testament.
One of the firmest, and most severe, warnings to mankind, is made in these last few verses of this letter. Not only does it apply to the Revelation letter, but equally to the entire New Testament word of God. It takes the form of the similar admonitions made to the Jewish nation regarding the Old Testament. Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the Lord your God which I command you (Deut. 4:2). Also, What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it (Deut. 12:32).
Here, regarding the Revelation letter and the New Testament, Jesus gives this ultimatum to all readers of His gospel message: If any man shall add unto these things, God shall add unto him the plagues that are written in this book. There is not to be anything added to God's word. It is given in its final form, and nothing else need be added, which may alter the meaning of that which has been written by inspiration of the Holy Spirit of God. Although some men and women in all ages have professed to having received additional revelations directly from God, these closing verses of the New Testament assures us that they are false teachers, whose message must, at all costs, be disregarded and completely avoided. And here is the severe warning by Christ to those that add to His word: God shall add unto him the plagues that are written in this book. Just as God caused severe punishments to come upon the apostate church that persecuted the church of Christ, so shall He punish, for eternity, those that add to His Holy Word.
Likewise, 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. To delete any part of God's word, or to reject a particular passage or book which it contains, is to altar it and change its true meaning. To deny a particular passage, to give it a false explanation, or, in any manner, to compromise God's word, can also be considered as taking away from the true meaning of the New Testament. To do so is sinful. Even with the severe, eternal punishment that is assured to those that change the meaning of any passage of the New Testament, mankind, for various self-satisfying, self- glorifying, and self-rewarding reasons, has sinfully disobeyed this direct command of God, and have added to, deleted from, or in any manner altered, the Holy Spirit-inspired New Testament gospel of Christ Jesus. Jesus assures all readers of God's word who take away from the words of the book of this prophecy, that their name will be blotted out of the book of life - they shall be forever excluded from that holy city - the New Jerusalem known as heaven.
Jesus Christ, approved the Revelation letter, as well as the entire New Testament, and testifies that it is, indeed, God's truths. The apostle John, could also be considered as giving his testimony to this, the Word of God. Jesus adds, Surely I come quickly, that is in the last days. The kingdom of Christ is firmly established. Jesus is now seated at the right hand of God and is currently ruling over His kingdom. He tells us with surety, I come quickly. Although the world may continue for ages to come, yet in God's time frame, the second coming of our Savior is deemed to be very soon. Death is eminently assured to all men and women of the world, and, at death, our eternal destiny becomes final. When physical death comes to mankind, the end can truly be said to have come quickly.And as long as life exists on earth, it will continue to come quickly to all mankind.
From Barnes' Notes, I found this appropriate comment to close this study of the New Testament: "For that glorious coming of the Son of God, when He shall gather His redeemed people to Himself, may all who read these notes be finally prepared." John adds these closing words: The grace of our Lord Jesus Christ be with you all. Amen.