The outline of what Jesus will be doing at that time is presented to us in Daniel 9:24. The Lord will do 6 things:
"Seventy weeks are determined For your people and for your holy city,
1. To finish the transgression,
2. To make an end of sins,
3. To make reconciliation for iniquity,
4. To bring in everlasting righteousness,
5. To seal up vision and prophecy,
6. And to anoint the Most Holy."
Notice several things. First, it is a period where though the times seem chaotic, it is actually orderly. It is all in control of God. The three series of 7-judgments apiece (Seals, Trumpets, Bowls) will be delivered in orderly fashion. The judgments unleash chaos, but their deliverance is orderly and controlled.
Another orderly aspect of the entire period, not just the Tribulation, is that He said it will take 70 weeks (70 bundles of 7 years, called shavua in Hebrew). This it adds up to 490 years total for Him to perform the 6 things. The Tribulation is the time for it all to come to the conclusion and so it is a time of demonstrable wrath. In further orderliness, He stopped the clock at 483 years. Nowhere was it promised to be 490 consecutive years! But they should have known that, because the interruption, too, was stated. In Daniel 9:25-26, a mere verse later, the angel told Daniel that after seven sevens and 62 sevens, Messiah will be cut off (vernacular for died) and the people of the prince who is to come (antichrist) shall destroy the city.
Jesus's entry into Jerusalem was 483 years to the day and then the clock stopped. Then Jesus took 2000 years to build His church, and when it reaches His quota, (Romans 11:25) then He will finish that last 7 years of the prophesied 70 weeks and accomplish the promised 6 things.
The angel also explained to Daniel that it is a time when God directs His attention to "your people" and "your holy city (Jerusalem). That does not mean He isn't paying attention to non-believers or non-Jews, and that nothing will happen to them during the Tribulation. Not at all. Jeremiah 30:7 calls it the Time of Jacob's Trouble, though, and its point is for the LORD to finish His promises to His people. #1 is to finish the transgression, and #2 says He will make an end to sins. This making an end to sins is an even that will affect everyone on the planet. God always sees the world through the lens of His people the Jews and through the central location of the Holy City. But all the world will be affected.
Secondly, note the progression of the 6 things. At the beginning, He allows the transgression to have its full expression. By the end, the Most Holy is anointed. The Most Holy is Jesus. Ahhh, what a day that will be! The Tribulation is the cap-stone to the final age of man where He allows the total outcome of rejection of the Holy Spirit to have its course. Like in Noah's day, where all of man's thoughts were only evil continually, (Gen 6:5) so it shall be again at the end of days (Matthew 24:37).
The Daniel 9:26 verse also promises that the end will come like a flood. This does not mean that there will be a flood of actual waters as in the first global judgment. As a judgment, He promised Noah that he would never drown the world again. (Gen 9:13). However, as part of the cataclysmic geo-physical upheavals during the Tribulation there will be floods and tides and hurricanes and tsunamis. However, the verse uses figurative language.The Hebrew word in Dan 9:26 is "sheteph; from shataph; a deluge (literally or figuratively) -- flood, outrageous, overflowing." He means that SIN will have its outrageous overflowing.
This flood language mirrors the language in Revelation 12:15. Midway through the Tribulation, the antichrist tears up the peace treaty he had confirmed with the Jews at the beginning of the Tribulation. He then persecutes them with all unholiness and evil. He goes after the Jews with an evil vengeance that makes the WWII Holocaust look like a picnic. "And the serpent poured water like a river out of his mouth after the woman, so that he might cause her to be swept away with the flood." Satan pours out his evil and sin flows over the world like a flood.
Floods have waters that rise, and rise and rise, eventually washing away all that is in its path. Even tsunamis which travel at jet speeds have waters that flow and rise accordingly. The end has began when Jesus ascended, but it has been 2000 years and we can see that the flood waters of sin are not lapping at our toes...are not sweeping against our waists...but the flood waters of sin seem like they are actually crashing over our heads. It seems the flood of sin in the world since the beginning is rising and rising, and now even crashing over our heads. It is like the famous photo of the lighthouse and its keeper
But we are not destined for wrath! (1 Thessalonians 5:9). Though sin tries to engulf us, it will not prevail against His church! (Matthew 16:18). Notice where the keeper is: INSIDE the Lighthouse. Would you want to be anywhere else when the wages of sin try to engulf you? No. You would not survive that wave. You would not survive the hidden reefs under the wave. (Jude 1:12) Being in the Lighthouse is the only safe place to be, in ages past and in this present age.
Jude says the apostates are "Raging waves of the sea, foaming out their own shame; wandering stars, to whom is reserved the blackness of darkness for ever." (Jude 1:12).
Peter says, "These men are springs without water and mists driven by a storm. Blackest darkness is reserved for them." (2 Peter 2:17).
Isaiah says, "But the wicked are like the tossing sea, which cannot rest, whose waves cast up mire and mud." (Isaiah 57:20).
What of us, individually? His word says that Hades will not prevail against His church, but what of each of us in the daily struggle against sin? Here: "The Lord is my light and my salvation; Whom shall I fear? The Lord is the strength of my life; of whom shall I be afraid?" (Psalm 27:1).
We are Light keepers, and our job is never more important than during the storm! We are in Christ as THE Light, but we keep His word hidden in our hearts. We are ambassadors of His glory and His truths. We keep His commands. We keep His flame alive on earth by staying In him and close to Him. It is important to be brighter during the storm and so let us be bright, by being full of peace and joy in these stormy times. Let the waves crash! We have the eternal Strength of the Light. Let others see, and come to Him.