For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. (Matthew 24:21)
And at that time shall Michael stand up, the great prince which standeth for the children of thy people: and there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time thy people shall be delivered, every one that shall be found written in the book. (Daniel 12:1)
For thus saith the LORD; We have heard a voice of trembling, of fear, and not of peace. Ask ye now, and see whether a man doth travail with child? wherefore do I see every man with his hands on his loins, as a woman in travail, and all faces are turned into paleness? Alas! for that day is great, so that none is like it: it is even the time of Jacob’s trouble; but he shall be saved out of it. (Jeremiah 30:5-7)
Based on the passages above, the second half of the 70th week of years will see a time of great tribulation unlike any other in history for Israel. Followers of Jesus Christ will also be impacted since we have been grafted into the root of the olive tree that represents God (Romans 11:16-24). This great tribulation is a result of the conflict between the woman in heaven and the great red dragon.
When Jesus begins to destroy Antichrist’s kingdom from Heaven there will be great tribulation for the people of Antichrist’s kingdom. In that sense, great tribulation extends until Jesus returns (Matthew 24:29-30).