The tribulation is prior to the return of Christ and is centred on Jerusalem.
It is at the time of the end.
Daniel 11:40 And at the time of the end shall the king of the south push at him: and the king of the north (that is: north of Israel) shall come against him like a whirlwind, with chariots, and with horsemen, and with many ships; and he shall enter into the countries, and shall overflow and pass over. 41 He shall enter also into the glorious land, and many countries shall be overthrown: but these shall escape out of his hand, even Edom, and Moab, and the chief of the children of Ammon. 42 He shall stretch forth his hand also upon the countries: and the land of Egypt shall not escape. 43 But he shall have power over the treasures of gold and of silver, and over all the precious things of Egypt: and the Libyans and the Ethiopians shall be at his steps. 44 But tidings out of the east and out of the north shall trouble him: therefore he shall go forth with great fury to destroy, and utterly to make away many. 45 And he shall plant the tabernacles of his palace between the seas in the glorious holy mountain; yet he shall come to his end, and none shall help him.
It will be a time of trouble
Daniel 12:1 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.
It is the time of Jacob’s trouble.
Jeremiah 30:1 The word that came to Jeremiah from the LORD, saying, 2 Thus speaketh the LORD God of Israel, saying, Write thee all the words that I have spoken unto thee in a book. 3 For, lo, the days come, saith the LORD, that I will bring again the captivity of my people Israel and Judah, saith the LORD: and I will cause them to return to the land that I gave to their fathers, and they shall possess it. 4 And these are the words that the LORD spake concerning Israel and concerning Judah. 5 For thus saith the LORD; We have heard a voice of trembling, of fear, and not of peace. 6 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? 7 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. 8 For it shall come to pass in that day, saith the LORD of hosts, that I will break his yoke from off thy neck, and will burst thy bonds, and strangers shall no more serve themselves of him: 9 But they shall serve the LORD their God, and David their king, whom I will raise up unto them. 10 Therefore fear thou not, O my servant Jacob, saith the LORD; neither be dismayed, O Israel: for, lo, I will save thee from afar, and thy seed from the land of their captivity; and Jacob shall return, and shall be in rest, and be quiet, and none shall make him afraid. 11 For I am with thee, saith the LORD, to save thee: though I make a full end of all nations whither I have scattered thee, yet will I not make a full end of thee: but I will correct thee in measure, and will not leave thee altogether unpunished.
All nations will become involved.
Joel 3:2 I will also gather all nations, and will bring them down into the valley of Jehoshaphat, and will plead with them there for my people and for my heritage Israel, whom they have scattered among the nations, and parted my land… 9 Proclaim ye this among the Gentiles; Prepare war, wake up the mighty men, let all the men of war draw near; let them come up: 10 Beat your plowshares into swords, and your pruninghooks into spears: let the weak say, I am strong. 11 Assemble yourselves, and come, all ye heathen, and gather yourselves together round about: thither cause thy mighty ones to come down, O LORD. 12 Let the heathen be wakened, and come up to the valley of Jehoshaphat: for there will I sit to judge all the heathen round about. 13 Put ye in the sickle, for the harvest is ripe: come, get you down; for the press is full, the fats overflow; for their wickedness is great. 14 Multitudes, multitudes in the valley of decision: for the day of the LORD is near in the valley of decision. 15 The sun and the moon shall be darkened, and the stars shall withdraw their shining. 16 The LORD also shall roar out of Zion, and utter his voice from Jerusalem; and the heavens and the earth shall shake: but the LORD will be the hope of his people, and the strength of the children of Israel. 17 So shall ye know that I am the LORD your God dwelling in Zion, my holy mountain: then shall Jerusalem be holy, and there shall no strangers pass through her any more.
The nation of Israel will suffer.
Zechariah 13:8 And it shall come to pass, that in all the land, saith the LORD, two parts therein shall be cut off and die; but the third shall be left therein. 9 And I will bring the third part through the fire, and will refine them as silver is refined, and will try them as gold is tried: they shall call on my name, and I will hear them: I will say, It is my people: and they shall say, The LORD is my God.
Christ will return to the mount of Olives with his saints.
Zechariah 14:2 For I will gather all nations against Jerusalem to battle; and the city shall be taken, and the houses rifled, and the women ravished; and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city. 3 Then shall the LORD go forth, and fight against those nations, as when he fought in the day of battle. 4 And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst thereof toward the east and toward the west, and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south. 5 And ye shall flee to the valley of the mountains; for the valley of the mountains shall reach unto Azal: yea, ye shall flee, like as ye fled from before the earthquake in the days of Uzziah king of Judah: and the LORD my God shall come, and all the saints with thee.
God gives more detail about the northern invasion of Israel through Ezekiel.
Ezekiel 38:2 Son of man, set thy face against Gog, the land of Magog, the chief prince of Meshech and Tubal, and prophesy against him, 3 And say, Thus saith the Lord GOD; Behold, I am against thee, O Gog, the chief prince of Meshech and Tubal: 4 And I will turn thee back, and put hooks into thy jaws, and I will bring thee forth, and all thine army, horses and horsemen, all of them clothed with all sorts of armour, even a great company with bucklers and shields, all of them handling swords: 5 Persia, Ethiopia, and Libya with them; all of them with shield and helmet: 6 Gomer, and all his bands; the house of Togarmah of the north quarters, and all his bands: and many people with thee. 7 Be thou prepared, and prepare for thyself, thou, and all thy company that are assembled unto thee, and be thou a guard unto them. 8 After many days thou shalt be visited: in the latter years thou shalt come into the land that is brought back from the sword, and is gathered out of many people, against the mountains of Israel, which have been always waste: but it is brought forth out of the nations, and they shall dwell safely all of them. 9 Thou shalt ascend and come like a storm, thou shalt be like a cloud to cover the land, thou, and all thy bands, and many people with thee. 10 Thus saith the Lord GOD; It shall also come to pass, that at the same time shall things come into thy mind, and thou shalt think an evil thought: 11 And thou shalt say, I will go up to the land of unwalled villages; I will go to them that are at rest, that dwell safely, all of them dwelling without walls, and having neither bars nor gates, 12 To take a spoil, and to take a prey; to turn thine hand upon the desolate places that are now inhabited, and upon the people that are gathered out of the nations, which have gotten cattle and goods, that dwell in the midst of the land. 13 Sheba, and Dedan, and the merchants of Tarshish, with all the young lions thereof, shall say unto thee, Art thou come to take a spoil? hast thou gathered thy company to take a prey? to carry away silver and gold, to take away cattle and goods, to take a great spoil? 18 And it shall come to pass at the same time when Gog shall come against the land of Israel, saith the Lord GOD, that my fury shall come up in my face. 19 For in my jealousy and in the fire of my wrath have I spoken, Surely in that day there shall be a great shaking in the land of Israel; 20 So that the fishes of the sea, and the fowls of the heaven, and the beasts of the field, and all creeping things that creep upon the earth, and all the men that are upon the face of the earth, shall shake at my presence, and the mountains shall be thrown down, and the steep places shall fall, and every wall shall fall to the ground. 21 And I will call for a sword against him throughout all my mountains, saith the Lord GOD: every man’s sword shall be against his brother. 22 And I will plead against him with pestilence and with blood; and I will rain upon him, and upon his bands, and upon the many people that are with him, an overflowing rain, and great hailstones, fire, and brimstone. 23 Thus will I magnify myself, and sanctify myself; and I will be known in the eyes of many nations, and they shall know that I am the LORD.
Jesus says there will be distress of nations, but those who understand the prophecies will recognise that their redemption is near.
Luke 21:24 And they (the Jews) shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled. 25 And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring; 26 Men’s hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken. 27 And then shall they see the Son of man coming in a cloud with power and great glory. 28 And when these things begin to come to pass, then look up, and lift up your heads; for your redemption draweth nigh.
The gathering of the nations to battle over Jerusalem is called in Revelation ‘Armageddon’.
Christ returns whilst the gathering to Armageddon is in progress.
Revelation 16:13 And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet. 14 For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. 15 Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame. 16 And he gathered them together into a place called in the Hebrew tongue Armageddon.
He returns ‘as a thief’ to raise the dead and gather his elect,
1 Thessalonians 4:16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: 17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. 18 Wherefore comfort one another with these words.
During the battle at Jerusalem Christ will return in glory with his saints to save Israel and establish the kingdom of God upon the earth.
Revelation 16:17 And the seventh angel poured out his vial into the air; and there came a great voice out of the temple of heaven, from the throne, saying, It is done. 18 And there were voices, and thunders, and lightnings; and there was a great earthquake, such as was not since men were upon the earth, so mighty an earthquake, and so great. 19 And the great city was divided into three parts, and the cities of the nations fell: and great Babylon came in remembrance before God, to give unto her the cup of the wine of the fierceness of his wrath. 20 And every island fled away, and the mountains were not found.
Revelation is a book of symbols so that ‘islands’ and ‘mountains’ represent the governments of this world who will not be able to resist Christ.
The kingdom of God will the restored kingdom of David.
Luke 1:32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
Christ will rule with his saints over the mortal population of the earth for 1000 years.
Isaiah 2:1 The word that Isaiah the son of Amoz saw concerning Judah and Jerusalem. 2 And it shall come to pass in the last days, that the mountain of the LORD’S house shall be established in the top of the mountains, and shall be exalted above the hills; and all nations shall flow unto it. 3 And many people shall go and say, Come ye, and let us go up to the mountain of the LORD, to the house of the God of Jacob; and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the LORD from Jerusalem. 4 And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more.
Revelation 20:6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
At the end of the millennial reign there will be a second resurrection and a final judgment in which sin and death will be eradicated and God will be ‘all in all’.
Paul explains what will happen.
1 Corinthians 15:20 But now is Christ risen from the dead, and become the firstfruits of them that slept. 21 For since by man came death, by man came also the resurrection of the dead. 22 For as in Adam all die, even so in Christ shall all be made alive. 23 But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming. 24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. 25 For he must reign, till he hath put all enemies under his feet. 26 The last enemy that shall be destroyed is death. 27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is excepted, which did put all things under him. 28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.
I hope you find this helpful.