First rapture is like a thief in the night. Nee writes in King and the Kingdom of Heaven...

"The second school of interpretation [posttribulation rapture onlyism] does not accept the idea of a secret rapture; yet its followers forget the word, “Behold, I come as a thief” (Rev. 16.15). A thief comes secretly, is never preceded by a band, and always steals the best."

There are many verses in Scripture talking about how Jesus come like a thief in the night before the Day of the Lord commences (His parousia during the 7 years of the Tribulation + Steping down on the mount of olives + Millennial Kingdom reign with His overcomer believers)Then Nee writes in chapter 16 (in "Come, Lord Jesus") which is during the bowls (bowls get poured during the last trumpet-the gleaning period when the battle is fought)...

"16.15 Here are still some words spoken to Christians. “Behold, I come as a thief are words spoken by the Lord to His church. These words may be spoken to those mentioned in Revelation 14.14-16 who are waiting to be harvested, or they may be spoken to the Christians who are left to be gleaned. The vintage spoken of in 14.17-20 is the same as the battle of Har-Magedon spoken of in 16.16. Therefore, 16.15 may refer either to the harvest of Christians before the battle of Har-Magedon or to Christians waiting to be gleaned after the harvest is gathered and before the battle is fought."

Another action of the thief in the night. But once Tribulation starts you can count down the days as Nee said...

"Were the entire body of believers to be raptured after the Tribulation, there would again be no need for us to watch and wait and be prepared. Knowing that the Lord would not come before the end of the three and a half year's period, we could live evilly up to three years five months and twenty-nine days. Yet such a concept violates the very principle of the Scriptures."

This latter paragraph doesn't seem like the activity of thief in the night if you can count it down.

The only way I know how to explain this is in two ways:

1) So much is going on that even to the church at that point, He will seem like a thief in the night, and

2) We don't know exactly when the last trumpet rapture and gleaning raptures take place exactly during the last 24 months of the 42 months of Great Tribulation (5 months for the fist woe, 13 months for the 2nd woe, leaving 24 months for the 3rd woe or 7th trumpet).

We don't know the exact day of the last trumpet rapture and resurrection, nor to how far in the gleaning raptures take place to the battle of Armageddon.

This action of the the thief in the night before the Tribulation and near the end of the Tribulation is now reconciled for partial rapture-echoing Nee's same sentiments.

And the problematic position of Post Tribulation Rapture onlyists who would be able to live evilly up to the return of Christ by counting down the days (for the bulk of the remaining days) and then giving their lives to Christ before the last trumpet rapture and resurrection still remains a problem for their view.