Dr. Mark Hitchcock
Faith Bible Church
Books about the end times frequently overlook the interval of time between the second coming of Christ and the official inauguration of the millennial kingdom. The Millennium will not commence the day after the end of the Great Tribulation. There will be a seventy-five-day interval.
This interval could be likened to the time between the election of a US president in November and the official inauguration in January. During this time, the president-elect appoints cabinet members, prepares his agenda, and doles out the spoils of victory to his faithful supporters.
Daniel 12:11-12 presents this interlude. Daniel 12:1-3 describes the time of coming Tribulation for Israel and then the resurrection of Old Testament saints. The Tribulation for Israel will last 1,260 days, which is 3½ years (Daniel 12:7). This is the latter half of the seven-year Tribulation. Then, after these great events we read the enigmatic words in Daniel 12:11-12: "From the time the daily sacrifice is stopped and the sacrilegious object that causes desecration is set up to be worshiped, there will be 1,290 days. And blessed are those who wait and remain until the end of the 1,335 days!"
As you can see, three future time periods are clearly delineated: 1,260 days, 1,290 days, and 1,335 days. Many commentators interpret these numbers symbolically, but as Leon Wood objects, "the numbers are so near in size that no symbolism would fit them. Moreover, numbers mentioned earlier in Daniel (e.g., 2,300 days, 8:14) have been found to be literal." 
So, what are we to make of these three time periods? The 1,260 days is not too difficult since this time period is frequently set forth in Daniel and Revelation as the final 3½ years of the Tribulation. The 1,290 days is thirty days beyond the end of the Tribulation, and the 1,335 days is another forty-five days beyond that. These time periods describe an interval of time between the end of the Tribulation and Christ's second coming and the beginning of the Millennium.
While we cannot be certain about everything that will transpire during this time, it is safe to say that during this time period Christ will remove the abomination of desolation, cast the Antichrist and the false prophet into the lake of fire (Revelation 19:20), throw Satan into the abyss (Revelation 20:1-3), judge those living on the earth (Matthew 25:31-46), resurrect and reward Old Testament and Tribulation saints (Daniel 12:1-3), and assign responsibilities for the administration of His Kingdom. During this interval, the celebration of the marriage supper will begin on the earth (Revelation 19:7-10), and possibly the construction of the millennial Temple will commence as well (Ezekiel 40-48). The fact that those who make it to the 1,335 days are blessed means that they have made it to the beginning of the millennial kingdom (Daniel 12:12). They have come through the judgments and are allowed to enter the kingdom. Leon Wood describes this time period:
Whatever occasion falls at the conclusion of these days is something good and desirable. There will be blessing for all those who attain it. The thought is thus suggested that it will be the actual starting point of the Millennium. Those who will have passed the judgment of Christ, during the preceding thirty days, would be those who will attain to it, after these forty-five additional days. What will be the need of these forty-five days? It may be the time necessary for setting up the governmental machinery for carrying on the rule of Christ. The True border of Israel (from the River of Egypt to the Euphrates, Genesis 15-18) will have to be established and appointments made of those aiding in the government. A period of forty-five days would again seem reasonable in which to accomplish these matters. 
John Phillips agrees, but adds a few more details:
No light is shed on the extra two and one-half months that follow. It might be that thirty days will be necessary for completing the mopping-up operations against the vast armies that have been deployed by both the East and the West at Megiddo and for bringing to an end all further hostilities worldwide. Also, the land of Israel will need to be cleansed of the dead. The temple, defiled by the Antichrist, will probably be demolished, too, before true worship can be established. Maybe all of these activities will take up the first month. Then, too, we learn from other Scriptures that the Lord intends to set up His throne in the Valley of Jehoshaphat, near Gethsemane, and to judge the nations in accordance with the criteria of Matthew 25. Possibly it will take the extra month and a half to gather the surviving people of the world from earth's remotest bounds to this great assize. The sheep will be separated from the goats. Swift doom will overtake those who sided with the Antichrist, who wore his mark, and who cooperated with his anti-Semitic laws. The remnant of the Jews and the redeemed from among the Gentiles will go on into the millennial kingdom, the nucleus of the new kingdom.
In any case, God pronounces them "blessed." The word, as usual, is plural. It can be rendered, as in Psalm 1:1 and elsewhere, "O the blisses of the person who..." or "Happy, happy is the one who..." The millennial kingdom will be worth waiting for. 
Three Time Periods in Daniel 12
- 1,260 days: the last half of the seven-year Tribulation
- 1,290 days: an addition of thirty days during which time the abomination of desolation continues in the Temple before its removal
- 1,335 days: forty-five more days after the 1,290 day period. The abomination of desolation will be removed, the Antichrist and false prophet will be cast into the lake of fire, Satan will be bound, the nations will be judged, Old Testament and Tribulation saints will be resurrected and rewarded, the marriage supper will begin, positions of authority will be meted out to God's people, and possibly the millennial Temple will be built or at least begun.
The Millennium will begin following the seventy-five-day interval. The King will take His throne, and the Kingdom of God will come to earth.
May all the godly flourish during his reign. May there be abundant prosperity until the moon is no more.
May he reign from sea to sea, and from the Euphrates River to the ends of the earth....
All kings will bow before him, and all nations will serve him (Psalm 72:7-8, 11).