An angel told Daniel the exact duration of the Time of Jacob's Trouble (3 1/2 years--Daniel 12:7), which is synonymous with The Great Tribulation. The angel goes on to mention an extended period of 75 days, which begin upon Christ's appearance at the Battle of Armageddon.
In order to enter into Christ's kingdom that will be established on earth, the angel said survivors of the Time of Jacob's Trouble/The Great Tribulation must also persevere and successfully arrive at the 75th day after the 2nd Coming of Christ.
So, what exactly will be happening during the 75 days?
Daniel 12:11-12 And from the time that the daily sacrifice shall be
taken away and the abomination that makes desolate set up (beginning of the Time of Jacob's Trouble) there shall be
a thousand two hundred and ninety days Blessed are they that
wait and come to the thousand three hundred and five and thirty days
In this passage, Daniel is told about 1290 days, which includes the 1260 days (forty-two months, 3 ½ years) of the Time of Jacob's Trouble, plus an additional thirty days. What will be happening during that additional thirty-days?
The additional 30-days is further extended by another forty-five days—bringing a total extension of seventy-five days; during which time, Daniel says that “Blessed are they who wait and come to the 1335th day.”
Thus, the seventy-five days appears to be divided into two time-periods of 30-days plus 45-days.
What will be happening during the first seventy-five days after Christ returns with his Bride and defeats his enemies at the Battle of Armageddon Jude14, Revelation 19:7-16?
Jesus' return at the Battle of Armageddon, marks the end of the Time of Jacob’s Trouble (which officially begins when the Abomination of Desolation is set up in the Holy Place -- Matthew 24:15-21).
According to Jesus, the Time of Jacob’s Trouble and The Great Tribulation are synonymous. Both begin exactly 3 ½ years before the Second Coming of Christ--which will end the Time of Jacob's Trouble.
We know this, because the Covenant with Death and Hades is a seven-year treaty that is broken exactly in the middle--3 1/2 years later--by the placing of the Abomination of Desolation in the Holy of Holies, in Jerusalem. This is a major difference between the rapture (which no one knows the day or hour) and the 2nd Coming (which the days can be counted from the time the Abomination of Desolation is set up in the Holy of Holies). The seven years immediately prior to the return of Jesus can be counted from the signing of the treaty that allows Jewish temple worship and daily sacrifices to begin (presently Islam controls the Temple Mount).
The Beast, his false prophet, and all who took the Mark of the Beast will be immediately gathered by angels and thrown into the Lake of Fire Revelation 14:9-11, 19:20.
During the first 30-days, the separating of the tares from the wheat will begin, starting with the tares Matthew 13:24-30, 36-43, Ezekiel 34:12-13, 38:12.
Now the great immigration, the final aliyah, of the elect (the Jews) from the four corners of the earth to Israel will begin, and a Jewish judgement will take place in Israel (Isiaih 60:4,9, Matthew 19:28).
After the Jewish Judgement, an anointing of King Jesus (coronation) will take place whereupon our Lord will finally allow his people Israel to acknowledge him as their King (Daniel 9:24, the 6th purpose of the seventy weeks). Remember, they tried to do this upon his entry into Jerusalem, but it wasn't the time yet, and fickle hearts betrayed him at his crucifixion.
The Marriage Supper of the Lamb will take place on earth (In Jerusalem) at some point during the first 75 days, before all the tares are disposed of. We know this, because some of the tares will attempt to crash the wedding reception Matthew 22:11-13.
Many, if not most, of these things will occur simultaneously.
The Judgement of the Nations Matthew 25 will take place during the 75 days and will conclude on the 1335th day. And that is why Daniel was told that those who survived to the 1335th day would be blessed. The sheep (both sheep nations and individuals--gentiles), the mortal survivors of The Great Tribulation, those who did not take the Mark of the Beast, and who survive the Judgement of the Nations, who bow before the ascendency of Israel as head nation (Isaiah 60:14) will be told to enter into the Joy of the Lord, into the kingdom prepared for them from the foundation of the earth Matthew 25.