The word tachu becomes relevant as a time reference only in the Book of Revelation. It is repeated there at the beginning and the end of the book (2:16; 3:11; 22:7, 12, 20), forming an inclusio that creates a general feel for the whole book that Christ’s “coming”/judgment of the matters discussed therein will fall tachu.
Preterists often argue that, since the word means "soon," this means that the events in Revelation must be taking place in the first century, in John's day. I, of course, agree that the events are taking place in the first century and in John's day, but do not agree that the word must be understood as "soon" in order to get this idea, nor do I agree with the non sequitur that this somehow means that the even describe therein is the destruction of Jerusalem in A.D. 70. That just doesn't pan out, as I'll discuss in a more extensive upcoming post.
Of the two most prominent meanings put forth by people, translating it as “soon” or “suddenly,” my interpretation of Revelation allows me to look at the evidence rather objectively, since either one of them fit into my interpretation of the book. I believe the events taking place in the background of the book refer to the persecution of Christians during the reign of Domitian toward the end of the first century A.D. BDAG relates that it can refer to a brief period of time with an emphasis on the speed of an activity or it can just refer to something that is done “without delay,” “quickly,” “at a rapid rate” (993). In other words, one meaning may be that it describes the time frame until which the action is performed (i.e., “soon”) and the other, and what I think is more likely the case in the context of Revelation, describes the manner in which the action is done (“quickly,” “suddenly”).
In fact, the word tachu itself seems to be used mainly in the New Testament to describe things that are done quickly (Matt 5:25; 28:7; 28:8; Luke 15:22; John 11:29), although one occurrence in Mark 9:39 seems ambiguous and could be interpreted either way. The meaning of “soon” seems most intended by its cognate tacheos, which does not appear in the Apocalypse. The other cognate, tachos, that does appear in Revelation twice (1:1; 22:6) is more ambiguous, however, sometimes evidencing a meaning of “quickly” (Luke 18:8; Acts 12:7; 22:18) and sometimes more ambiguous so as to possibly have either meaning (Acts 25:4; Rom 16:20; 1 Tim 3:14). Although, even here, BDAG states that the word can refer to a period of time that focuses on the “speed of an activity or event” (992).
Revelation is made difficult, not so much by the argument of the book itself, but because our presuppositions of what the book is about often don’t accord with what the book says, and hence, it becomes incomprehensible. These things either must be made up of an obscured symbolism because of their taking place in the distant future, or they make up a symbolic description of some past event. Both of these positions tend to think that the Apocalypse is about detailing the “end” (whether the end of a covenant age or the end of the world), whether in literal or symbolic form. Both of these positions, however, could not be more wrong.
The Apocalypse is not about the end of anything. It simply references the end (what I refer to as the macro-event) and puts it together with an immediate judgment that Christ is making upon the churches, arguing that if Christians align themselves with the world via a compromised form of idolatry and worshiping the beast, they will meet the same fate as the world, typified in the Roman Empire. This judgment consists of a micro-event in terms of the fact that it is not a universal or cosmic event, but rather a localized event that foreshadows the larger one, and should be seen in light of the larger event. What this means is that the book is not attempting to describe the macro-event, but merely to place the micro-event in the context of the macro-event, whatever it may look like, in order to communicate a message to the first century church concerning Christ’s coming to it in judgment (e.g., “I am coming to you” 2:5, 16; 3:3).
Hence, even though the words tachu and tachos convey more of an idea concerning something happening suddenly or someone doing something quickly/hastily, rather than conveying the time frame from what is said to the execution of the event, it becomes a moot point, since Christ is saying to the churches that He is coming quickly to render judgment upon them (which is why the rest of the book should be read in light of the ecclesiastical letters in the beginning of the book, which function as the book’s key). He is already at the door, judgment is about to take place for these churches, and He will come suddenly, like lightening and like a thief in the night to render that verdict. Hence, the churches are told to repent of their living like the world, and further shown by the rest of the book that those who live in a Christless antinomianism really belong to the world, and hence, will receive its judgment. The book, therefore, is not about describing end time events, but rather merely references common apocalyptic themes of the end times in order to convey the concepts of the visible and invisible church and where their respective allegiances truly lie.
The book has absolutely nothing to do with the fall of Jerusalem. Christ’s “coming” in the context is His coming to judge the church, and that is merely linked to His future eschatological coming in the flesh, where every eye will see Him. This joining the micro and macro events together as a single event is a common literary feature in apocalyptic literature. It does not intend to convey the idea that the micro-event and the macro-event actually occur at the same time, or that the micro event is the macro event. To read it as such is to misunderstand the ancient worldview at work in these texts.
The book itself is set in the backdrop of Domitian’s persecution, as the book is primarily concerned with condemning Christians who compromise and “eat food sacrificed to idols” (2:14, 20) in order to participate in the larger culture. This has its specific reference in John to those who participate in idolatry and the imperial cult (e.g., worshiping the beast and his image is condemned numerous times throughout the book, Rev 11:7; 13:4, 12-14; 14:9, 11; 15:2; 16:2; 17:3-7; 19:19; 20:4). As the beast is the enemy of Christ and His people, worshiping the beast is antithetical to worshiping God through Jesus Christ. Christ, in Revelation, therefore, comes to judge His Church concerning the matter.
When Christ tells the church that He is coming tachu. He is not saying that He is coming soon, since He is actually already there among them (2:1). What He is saying is that when judgment falls, it is going to fall suddenly and without warning. In fact, the rebuke He gives is already a part of that judgment. It, hence, has already begun, and unless they repent, they will be removed from being considered His people (2:5).
This sudden judgment is captured in the image of a thief who comes quickly in the night (3:3). It is sudden and before one knows it.
In fact, the thief in the night imagery is supplemented with other images throughout Scripture that describe judgment as a sudden event for which unrepentant people are not prepared. It is described as birth pangs coming upon a pregnant woman (1 Thes 5:3), and a trap that suddenly springs on you (Luke 21:34). The word in Luke here is aiphnidios “suddenly.” The only way to avoid a surprise judgment that suddenly falls is to repent and be ready by living in faith, love, and hope (1 Thes 5:8). The final imagery is lightening flashing from one side of the sky to the other (Matt 24:27; Luke 17:24). Lightening is not flashing “soon,” but suddenly and without warning.
This is what tachu conveys, then. It is not that the trap shuts “soon,” or that birth pangs come upon a woman “soon,” or that the thief comes “soon,” or that lightning flashes “soon.” It is that the trap shuts suddenly, abruptly, without warning. Birth pangs come upon a pregnant woman seemingly out of nowhere. They fall upon her suddenly and without warning. The thief does not come soon in the night, but rather quickly. He comes without warning and at a great haste so that he can quickly leave with one’s goods. The lightning flashes quickly across the sky. It is sudden and without warning.
This suddenness is the type of judgment conveyed throughout the book. All of the plagues fall upon Babylon the Great in one day (18:8) and with a sudden violent force (v. 21). In another description the city, the mountains, and all of the islands of the world fall with a sudden, violent earthquake (6:14-17; 16:20).
The Lord conveys with the word tachu, then, that those who do not repent will also be overtaken suddenly along with the world (2:16; 3:3). Since they wish to partake of the benefits of attending the festivals that honor the gods and the emperor, they can also partake of its sudden judgment and destructive end that leads to the lake of fire and brimstone.
Hence, the message of the book is a message of repentance so that the faithless are restored to right worship and those who have overcome the beast by not loving their lives even to death are encouraged. The suddenness of Christ’s judgment strikes fear in the unfaithful and gives hope to the faithful.