The tribulation begins when the Antichrist makes a seven-year peace treaty with Israel that allows the Jews to offer sacrifices in the rebuilt temple in Jerusalem. The events are spelled out in Daniel 9:27.
"And he will make a firm covenant with the many for one week, but in the middle of the week he will put a stop to sacrifice and grain offering; and on the wing of abominations will come one that makes desolate, even until a complete destruction, on that is decreed, is poured out on the one who makes desolate."
The first three and one-half years are a time of peace. The second three and one-half years begins when the Antichrist breaks his covenant or treaty with Israel, invades the land, and sets up an abominable image of himself in the temple in Jerusalem. The last half of the seven-year period is referred to as "42 months " in Rev 11:2, as "1260 days" in Rev 11:3 and Rev 12:6, and "time, times, and half a time" in Daniel 7:25 and 12:7. It is also referred to as the "great tribulation" in Matthew 24:21.
The Tribulation is God’s judgement on the earth, which comes in three waves containing seven seal judgements, seven trumpet judgements, and seven bowl judgements. The three waves of judgements are described in Revelation 6-16.
The Seven Seal Judgements
- First seal (6:1-2) – White horse: Antichrist
- Second seal (6:3-4) – Red horse: War
- Third seal (6:5-6) – Black horse: Famine
- Fourth seal (6:7-8) – Pale horse, Death and hell
- Fifth seal (6:9-11) – Martyrs in heaven
- Sixth seal (6:12-17) – Universal upheaval and devastation
- Seventh seal (8:1-2) – The seven trumpets
The Seven Trumpet Judgements
- First trumpet (8:7) – Bloody hail and fire: One-third of vegetation is destroyed
- Second trumpet (8:8-9) – Fireball from heaven: One-third of oceans polluted
- Third trumpet (8:10-11) – Falling star: One-third of fresh water polluted
- Fourth trumpet (8:12) – Darkness: One-third of the sun, moon, and stars darkened
- Fifth trumpet (9:1-12) – Demonic invasion: Torment
- Sixth trumpet (9:13-21) – Demonic army : One-third of the population killed
- Seventh trumpet (11:15-19) – The kingdom: The announcement of Christ’s reign
The Seven Bowl Judgements
- First bowl (16:2) – Upon the earth: Sores on the worshipers of the Antichrist
- Second Bowl (16:3) – Upon the seas: Turned to blood
- Third bowl (16:4-7) – Upon the fresh water: Turned to blood
- Fourth bowl (16:8-9) – Upon the sun: Intense, scorching heat
- Fifth bowl (16:10-11) – Upon the Antichrist’s kingdom: Darkness and pain
- Sixth Bowl (16:12-16) – Upon the Euphrates River: Armageddon
- Seventh bowl (16:17-21) – Upon the air: Earthquakes and hail
God will use the Tribulation to humble the Jewish people and to bring them to Himself. He will also use the Tribulation to punish the Gentile nations (non-Jewish people) and all unbelievers for rejecting Jesus (Isaiah 24:1-6). The Tribulation ends with the Second Coming of Christ (Rev 19:11-21).
Read more in The Complete Book of Bible Prophecy