Problem: Bible students include the day of the Lord in the seven years of tribulation, when in fact the day of the Lord does not begin until the seven last years of Daniel's prophecy have come to an end.
2TH 2:1-3 Concerning the coming of our Lord Jesus Christ and our being gathered to him (the rapture), we ask you, brothers, not to become easily unsettled or alarmed by some prophecy, report or letter supposed to have come from us, saying that the day of the Lord has already come (trumpet judgments and bowls of wrath). Don't let anyone deceive you in any way, for that day (the day of the Lord) will not come until the rebellion occurs and the man of lawlessness is revealed, the man doomed to destruction.
In these three verses Paul is talking about the rapture and the judgments of the day of the Lord, and how the day of the Lord will not come until the man of lawlessness sits in the temple of God proclaiming that he is God.
Peter sums up what the day of the Lord is all about:
2PE 3:10 But the day of the Lord will come like a thief. The heavens will disappear with a roar; the elements will be destroyed by fire, and the earth and everything in it will be laid bare.
What Paul is trying to point out in 2TH 2:1-3 is that the rapture of the church precedes the day of the Lord. Both in the old testament scriptures, and in the new testament. The term "the day of the Lord" speaks of our Lord's wrath that he pours out on the earth, and it has nothing to do with Daniel's prophecy of the seventy weeks. Daniel's final week of years is about the Antichrist, and the great deception he pulls off on the earth dwellers when he, along with the False Prophet, convince them that the Antichrist is God.