The following is an excerpt from Dr. Thomas Holland's Crowned With Glory, ©2000, used with permission.
Revelation 22:19 -"book of life" and the last six verses of Revelation 22
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.
While the focus of this verse deals with the phrase "book of life" as opposed to "tree of life." the issue is deeper. The manuscript Codex 1r used by Desiderius Erasmus to produce his Greek New Testament is missing the last six verses of Revelation chapter twenty-two. It is thought that Erasmus took the Latin Vulgate and retranslated these verses back into Greek.  Assuming this hypothesis is true we must ask ourselves the following questions. First, if Erasmus did in fact make use of the Latin Vulgate to supply these last six verses, has the usage of the Latin corrupted the text? Second, was Codex 1r really the only Greek manuscript used by Erasmus for this passage?
Certainly the Latin Vulgate and the Greek Textus Receptus are similar in these last six verses. This, of course, would be natural if the Latin was based on early Greek manuscripts that correspond with the Textus Receptus. We must remember that most of the Greek manuscripts of the second, third, and fourth centuries have not survived the passage of time. However, the Vulgate and the Textus Receptus are not identical either. For example, the conclusion of Revelation 22:20 reads in the Receptus, Amen. Nai, erchou, kurie Iesou (Amen. Even so, come Lord Jesus). The Latin reads, amen veni Domine Iesu (Amen come Lord Jesus). The Textus Receptus includes an additional affirmation nai (even so), an addition not found in either the Greek Critical Text or the Latin Vulgate.
If Erasmus did translate back into Greek from the Latin text, he did an astounding job. These six verses consist of one hundred thirty-six Greek words in the Textus Receptus, and one hundred thirty-two Greek words in the Critical Text. There are only eighteen textual variants found within these verses when the two texts are compared.  Such textual variants, both in number and nature, are common throughout the New Testament between these two Greek texts. For example, the preceding six verses, Revelation 22:10-15, have fourteen textual variants which are of the same nature, and in Revelation 21:3-8 we find no fewer than twenty textual variants. One would expect, therefore, a greater number of textual variants if Erasmus was translating from the Latin back into Greek, and yet the two texts are extremely close. Even if he did translate from the Latin into Greek it would have no bearing on the doctrine of biblical preservation. Preservation simply demands that God has kept and preserved the words throughout the generations from the time of their inception until this present day and even beyond. It does not demand that these words be preserved in the original languages only.
However, this brings us to our second question. Did Erasmus really translate the Latin back into Greek? Textual scholar Herman C. Hoskier argued that Erasmus did not do this. Instead, he suggests that Erasmus used other Greek manuscripts such as 2049 (which Hoskier calls 141), and the evidence seems to support this position.  Manuscript 2049 contains the reading found in the Textus Receptus including the textual variant of Revelation 22:19. To this we can also add the Greek manuscript evidence of 296, and the margin of 2067.
Additionally, the Greek text copied by Erasmus in Revelation 22:16-21 reflects a consistency that is found elsewhere in the Textus Receptus, suggesting that it was copied from other Greek manuscripts and not translated from the Latin back into Greek. In Revelation 22:16 we find the phrase tou dabid (the David) in the Textus Receptus as opposed to the Critical Text's dauid (David). While the English would translate the two identically, it is interesting to note that in Revelation 3:7 we find the same thing. In that passage the Textus Receptus places the definite article before the name of David just as it does in Revelation 22:16, while the Critical Text does not use the definite article before David's name in either passage.
To counter this it has been noted that within the text of Erasmus at Revelation 22:16-21 there are a few unusual spellings, for example elthe (come) instead of the normal erchou (come). This suggests that Erasmus was copying from a Greek manuscript and not translating from the Latin. Erasmus, it should be remembered, was one of the greatest scholars and thinkers of his day. He was fluent in Greek and several other languages. He would have known that the normal New Testament word for come is not elthe but is instead erchou. In fact, Erasmus used erchou in Revelation 22:7; 22:12; and even in 22:20. There must have been a reason for Erasmus to depart from the normal form of the word and write elthe in 22:17. Moreover, the Latin for come in 22:17 is the same Latin word in 22:20, veni. This further suggests that Erasmus was not really translating from the Latin, but was using an additional Greek manuscript other than Codex 1r.
Likewise, there is textual evidence for the reading book of life instead of tree of life. As noted above, the reading is found in a few Greek manuscripts. It is the main reading among the Latin witnesses. The phrase book of life is also the reading of the Old Bohairic version. Finally, it is the reading found in the writings of Ambrose (397 AD), Bachiarius (late fourth century), Primasius (552 AD) and Haymo (ninth century).
One must also consider the internal evidence. The phrase tree of life appears seven times in the Old Testament and three times in the New Testament. In these verses we are told we will be able to eat of this tree, and that this tree of Eden will reappear in Eternity. The idea that one can have their share taken away from the tree of life seems abnormal to Scripture. However, the phrase book of life appears seven other times in the New Testament (Phil.4:3; Rev. 3:5; 13:8; 17:8; 20:12, 15; and 21:27). In each case we find the book of life either contains or does not contain names, or names are blotted out of it. Therefore, the phrase, "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," is extremely consistent with the biblical texts.
As can be seen from this text, the warning is ominous. While one may understand this passage to apply only to the book of Revelation, it is clear from other passages that the same is true of the whole of Scripture (Deuteronomy 4:2; Proverbs 30:6). When applied to the verses discussed in this chapter we must conclude that somewhere in the process of transmission someone either added to the text or omitted from it. There's the rub, and it should be taken seriously. Scholarship is a noble and honorable profession. However, it ceases to be both if it seeks to usurp the authority of the Lord God. After all, our commitment does not so much rest with our scholarship as it does with the ultimate Scholar.
 Erika Rummel, Erasmus' Annotations on the New Testament: From Philologist to Theologian (Toronto: University of Toronto Press, 1986), 93. It is claimed that Erasmus openly declares in the Annotations of his 1516 edition (page 675) that he "ex nostris Latinis supplevimus Graeca" (supplied the Greek from the Latin). Thus the claim that last six verses of Revelation chapter twenty-two were retranslated from the Vulgate into Greek. However, the reprint of the 1516 edition of Erasmus does not contain this phrase on page 675 of his Annotations, which is the conclusion of his notes on the book of Revelation. Nor is such a phrase found elsewhere in that edition.
 The following are the seventeen textual differences found in these six verses. Because of the nature of this footnote, I have not transliterated these Greek words.
Textus Receptus Critical Text
tou dabid (the David) dauid (David)
kai orqrinoV (and morning) o prwinoV (the morning)
elqe (come) ercou (come)
elqe (come) ercou (come)
elqetw kai (let him come and) ercesqw (let him come)
lambanetw to (let him take the) labetw (let him take).
summarturoumai gar (for I testify to everyone) marturw egw (I testify to everyone)
epitiqh proV tauta (should add to these things) epiqh ep auta (adds to them)
bibliw (book) tw bibliw (the book)
afairh (should take) afelh (takes away)
biblou (book) tou bibliou (the book)
afairhsei (shall take away) afelei (shall take away)
biblou (book) tou xulou (the tree)
kai twn (and the) twn (the)
en bibliw (in book) en tw bibliw (in the book)
amhn nai ercou (Amen; even so, come) amhn ercou (Amen, come)
kupiou hmwn ihsou cristou (our Lord Jesus Christ) ihsou cristou (Lord Jesus)
meta pantwn umwn amhn (with all you Amen) meta twn agiwn (with all)
 H. C. Hoskier, Concerning the Text of the Apocalypse, vol. 2 (London: Bernard Quaritch, Ltd., 1929), 644.