The teaching of a future 7-year "Tribulation Period" is a work of fiction. In Matt 24 Jesus tells us about those days which precede His coming. In Matt 24:15 Jesus links this period to the seventieth week, the last seven years of Daniel’s notable prophecy (Dan 9:24-27). However, neither Jesus nor any other Biblical author identifies these seven years as "The Tribulation" or "The Tribulation Period". There are three distinct periods spoken of in the seventieth week. In the Olivet Discourse Jesus focuses upon the first two of these periods, “the beginning of sorrows” (Matt 24:8), and the days of “great tribulation” (Matt 24:21). The last of these periods, the beginning portion of “the day of the Lord,” He only mentions the beginning of it and doesn't identify it by name. The beginning of the day of the Lord will involve Christ’s arrival, His revelation to all the world, and the catching up of the saints.
These three periods, “the beginning of sorrows,” “great tribulation,” and “the day of the Lord (part 1),” come in that order, the one after the other, likely starting at the beginning of the seventieth week. (Note: While it is certain that the "beginning of sorrows" events flow into the days of great tribulation in the middle of the seven years, there is no text that demands that they begin at the opening of the seventieth week. However, what is certain is that all the events that Christ described as signs of His coming will take place within the generation that witnesses His Parousia (Matt 24:33-34). This means that a single generation will see the beginning of sorrows, the days of great tribulation, and the parousia of Christ initiating the day of the Lord. The name "The Tribulation" is a man made contrivance intended to equate the seventieth week with the day of the Lord. Although they will overlap, the day of the Lord beginning at some point in the second half of the seven years, they are not equal. Neither is the seventieth week equal to the days of great tribulation which begins in the middle of the week with the abomination of desolation and continues until it is cut short by Christ's return.
It isn't until the middle of the week that there is anything said to be unprecedented taking place, that being the unprecedented persecution that Jesus called great tribulation (Matt 24:15, 21; Dan 9:27; 12:1). Before the great tribulation begins in the middle of the week Jesus spoke of a time of false Christs, wars and rumours of wars, famines, pestilence, and earthquakes (Matt 24:4-8). This he said was the beginning of sorrows. These are nothing new to human history. The happenings which make up “the beginning of sorrows” take place before the unprecedented persecution of the elect (the great tribulation) begins. The beginning of sorrows will be a difficult time for many, but no more so than is true now in various places around the world or has been true at times in the past. The beginning of sorrows corresponds with what John sees at the opening of the first three seals (Rev 6:1-6).
What comes next is the days of great tribulation period as described in Matt 24 verses 9 thru 29. Satan, in his wrath, having been cast from Heaven (Rev 12:12), empowers the Beast to make war against the saints and he prevails over them (Rev 13:4). This unprecedented violent persecution Jesus called “great tribulation” (Matt 24:21). When it would appear that the Beast and his followers are about to rid the earth of every last believer (Matt 24:22; Luke 18:7-8, Rev 6:9-11), we will be rescued by Christ (Dan 12:1; Matt 24:13, 31; 1Thes 4:15-17; 5:9; Isa 26:19-21), after which Christ will pour out His wrath upon our persecutors (1Thes 5:2-3; 2Thes 1:6-10). Technically, we, the church, having been appointed unto affliction (1Thes 3:2) and having been given unto suffering for Christ’s sake (Phil 1:29) are in a period of tribulation at this present time. But we are not in the seventieth week, nor are we experiencing the unprecedented persecution of the days of “great tribulation.” However, in the middle of the seventieth week, the persecution that we are experiencing now will increase in scope and severity to an unprecedented level (Matt 24:21; Dan 12:1; Jer 30:7). It is important to note that this persecution is not focused upon the beast worshiping earth dwellers, it is focused upon the followers of Christ, the elect (Matt 24:9c; 22, 24, 31). This great tribulation will continue throughout the second half of the seventieth week until the Lord cuts it short (Matt 24:22) with a great earthquake (Rev 6:12; Matt 24:29; Lk 21:25-26). This mega earthquake moves every mountain and every island out of its place (Rev 6:14). Isaiah described it as Christ arising to shake terribly the earth (Isa 2:19). The earthquake is immediately followed by the cosmic sign which comes before the day of the Lord as mentioned by Joel (Joel 2:31) and Peter (Acts 2:20). This cosmic sign serves to announce to the world that Jesus Christ is coming in the clouds, in glory, with the mighty angels. At that point Christ will be revealed. It is His REVELATION [apokalupsis] (Luke 17:30, 1Cor 1:7, 2Thes 1:7, 1Peter 1:7, Rev 1:7, Matt 24:30, Titus 2:13). It is after the revelation of Christ that the saints are resurrected, changed, and raptured. Once we are safely removed from the earth and the 144,000 are sealed, God’s wrath begins to fall upon the unbelieving, Beast worshiping, earth-dwellers in the trumpet and vial judgments. There is no seven year tribulation period, that is eschatological fiction.