The book of Revelation generates feelings of awe and fear in many readers because contains various images and phrases that are difficult to grasp, and also grim pictures of future. But the book of Revelation even with its mysterious quality is one of the most optimistic books of the Bible.
First of all, right from the beginning John, the author of the book writes: "Blessed is the one who reads the words of this prophecy, and blessed are those who hear it and take to heart what is written in it, because the time is near" (Rev. 1:3). The same thing is repeated in the end (Rev. 22:7). Thus, this book is very important for every Christian to the degree that the author blesses in a special way its readers. The next sentence seems to note the reason. the book contains important messages and blesses those who keep them.
Besides the fact that in Revelation once more the main elements of Christian teaching are repeated, this book is important for another reason: the book of Revelation is the one in which the whole history of the universe is summarized; not only the beginning, as in the Genesis, not only the First Coming of the Lord and the spiritual salvation but the whole earthly history, its end and even beyond the end – the glorious eternal life.
Though information about the eternal life, Second Advent are scattered throughout the whole Bible, and the Revelation itself repeats often parts and ideas from those books, all these information is summarized, gathered as one solid and marvelous image, which is so important for the believer that John solemnly blesses twice the readers and keepers of those words. I think the reading of the Revelation should be started from here. This means the believers should make clear that they must keep because the blessing is given not to those who make some calculations about the end of the world or correlate some modern events to certain lines of the Revelation, but to those who keep the words contained there. And here the question comes forward: what words written in Revelation should be kept? Of course, the commandments because everywhere in Bible where there is a word about keeping something, God's commandments are meant. Therefore, in the succession of events which are registered in the Revelation one has to see what commandment is given by God to His believers. It is not accidental that the Revelation starts with commandments given to seven churches, which again points to the importance of them.
On the other side, it is true that the Revelation is full of hidden mysteries, which are referred as such in this book itself: "This calls for wisdom..." (Rev. 13:18) or "This calls for a mind with wisdom" (Rev. 17:9) or "And when the seven thunders spoke, I was about to write; but I heard a voice from heaven say: "Seal up what the seven thunders said and do not write it down" (Rev. 10:45). A similar command is contained in the Gospels when the Lord speaking about the last times, says: "Let the reader understand" (Mark 13:14). The same regards the Babylon city of Revelation of which is written: "Mystery great Babylon" (Rev. 17:5), which hints that the identity of that city is concealed and will emerge in its proper time.
Now, in the Revelation we have simultanious admonitions-blessings to read the book and be cautions that some parts of the content may be difficult to understand and are hidden, and the discreet reader must be able to distinguish the useful commandments and be guided by them, and on the other hand, to treat complicated words with caution and humbleness because not all prophesies are for the given time which God said to Daniel about the last days: "Go your way, Daniel because the words are closed up and sealed until the time of the end" (Dan. 12:9).
Another principle to be guided by is, of course, the need to explained the word of Bible by the Bible itself. This follows from the word of apostle Paul: "The whole Book is God-spirited". Therefore if the author of all books of the Bible is one, then commenting a book of the Bible one has to use other books of Bible. Especially trustworthy are those commentaries and explanations that are supported by similar verses of New and Old Testaments.
Revelation shows that the forces of evil will temporarily triumph over the Church when it says: "The beast that comes up from the Abyss will attack them, and overpower them and kill them" (Rev. 17:9). But the final victory belongs to the Lord and through Him – to His Church, though this victory will come after great afflictions, in times when no flesh is nearly able to live. This confirms the word of Jesus that "without Me you can do nothing" (Jn. 15:5). This is probably the most important message of the Revelation: to do everything in the name of the Lord and by relying on is power.
There are topics on the last times which are general in Gospels and Revelation. One of them is the topic of false teachings. The Lord says in the Gospels that great errors should be and false christs should emerge, and strictly warns not to follow them and not to abandon the faith due to the false teachings: "Behold, I have told you before" (Mt. 24:25), thus underlining especially important action – to be vigilant against false teachings, their main sorts being the sects which are spread today. In the Revelation more concretely the main deceiving person who will act during the last 3.5 years – the false prophet. Very important is a point that is mentioned both in Gospels and in the book of Revelation that these false teachers will accomplish many signs, or in other words, miracles. Today's people who have little acquaintance with spiritual issues think that the miracles are a strict proof that those who accomplish them, are doing them with divine power. But the Lord here again gives clear indication: "For there shall arise false christs and false prophets, and shall shew great signs and wonders; insomuch that, if [it were] possible, they shall deceive the very elect" (Mt. 24:25). In last days the Christians should be especially cautious so that not to believe those miracles because those miracles will be very powerful, and when nearly all the world through powerful contemporary media would be gone astray and following those false teachings, blessed will be those few who will stand firm in their faith and would not follow those false teachings. In the Revelation the deeds of those faithful are indicated in words having the same meaning: "victory over the beast, and over his image, and over his mark, [and] over the number of his name" (Rev. 15.2), by which collectively are indicated all the errors and violence, though today it is difficult to indicate exactly what is the meaning of the statue, number of name, mark but these things will be important for those who will live during those last 3.5 years of Antichrist. There are many data about the Antichrist in Old and New Testaments that will allow to identify him when arrives. In this context, the part concerning the number 666 of Antichrist's name, which is abused in many calculations especially in sectarian circles, should be considered as only one of those signs, and the one, which will be necessary only for people of last years, so that they might once again be convinced that the Lawless one if their time, about whom there are so many other data, is really the Antichrist.
Another circumstance, which again is seen in combined consideration of Gospels and Revelation, is the duration of the last time's afflictions that in Gospels is indicated as short time. "And except those days should be shortened, there should no flesh be saved" and adds that those days will be shortened for the sake of His elect ones, i.e. for His Church (Mt. 22:24). In the Revelation, this time is indicated more precisely – 1260 days (Rev. 12:6 and 11:3), 42 months (Rev. 13:5 and 11:2) and again, as in Gospels "he must be loosed a little time" (Rev. 20:3). The frequent repetition of this number might be considered as an additional comfort by which Christians of the last time might persevere the difficulties. This number is present also in the prophecy of Daniel: time, times and half time (Dan. 12:7).
There is a beautiful mystery in Gospels, which gets its further development in Revelation. This mystery seems to complete the whole history of mankind from the viewpoint of spiritual maturity. And this is very proper for the last book of the Bible. This mystery is expressed in the words of the Lord when He speaks about the end of the world and His Advent: "For nation shall rise against nation, and kingdom against kingdom: and there shall be earthquakes in diverse places, and there shall be famines and troubles: these [are] the beginnings of birth pangs" (Mk. 13:8). In another place He speaks about afflictions: "A woman when she is in travail has sorrow, because her hour has come: but as soon as she is delivered of the child, she remembers no more the anguish, for joy that a man is born into the world" (Jn. 16:21). In the Revelation, there is another picture, the image of a woman clothed with the sun, and the moon under her feet and who and she being with child cried (Rev. 12:1-2), who, according to the commentary of fathers, represents the Church. Connecting these several pictures we see a comparison: the afflictions of the last times (especially the 3.5 years) are represented as a birth pangs of the whole mankind (more exactly – Church, for whom God created the world). And as a woman has to bear the birth pangs until the child is born, so the Church has to go through afflictions until her delivery. Even arithmetically this comparison is noteworthy and proper, though we do not insist on it as on a doctrine.
Indeed, if we take the history of mankind 6000 years (in other versions of the Bible 7000 years), the relation to the last 3.5 years is from 1700 to 2000. And when we take the duration of pregnancy of a woman 280 days, which is 6720 hours, and the duration of delivery, according to medical data is approximately 3-4 hours , then the relation of these two numbers is approximately 1700. It is assumed that both the duration of time after the creation of the man and the duration of birth pangs are not precise numbers. Nevertheless, the mentioned arithmetics is a notable circumstance that these afflictions are comparable with the difficulties resulting in the birth, emergence of new mankind, about which frequently and with pleasure speaks apostle John in Revelation, starting with the promises given to Churches that contain the word "He that hath an ear, let him hear what the Spirit saith unto the churches", in other places (Rev. 7:9-17, 14:1-5), especially starting from the chapter 21 until the end when the New Jerusalem and eternal life are described. Therefore, having this comparison, I'd like to underline that it is not surprising that the most important message of the Bible, which concerns the final salvation and rebirth of mankind, is ingrained in nature, moreover, in the nature of a man, the more so as it is profoundly connected with such a phenomenon as the birth of a man. This once again confirms that the author of the Bible and nature is the same – Holy Trinity.
 Actually, according to some data, the duration of childbirth could be longer in some cases. But we have to remember here that the Lord promised to make that period shorter (Mt. 24:22), and it would be quite justified to take the shorter duration.