That lie has been refuted already that Darby invented the Rapture.
When it comes to watching, I believe it is talking about being ready for Jesus to return, how and what are we to watch? I would say our own state, spiritually speaking. Many post-tribbers play the pin the tail on the antichrist game and the lets prepare for doomsday stock up on supplies game.
I came to my conclusion based on this verse, that it is our spiritual state the Lord is most concerned with:
1 John 3:3
And everyone who has this hope in Him purifies himself just as He is pure.
Yeah, I agree! The reference to Darby and MacDonald, is just a created apologetic in an attempt to refute the promise of the Lord coming to get His church prior to the tribulation period.
It is really amazing that, besides all the scripture that we have to support a pre-trib gathering, that believers actually think that, the Lord would first put His bride through His wrath and then gather her afterwards. One of the major problems with the mid and post-trib view, is a lack of understanding of the severity and magnitude of that time of wrath. As I have posted many times, with just the accumulation of the first four seals and the 6th trumpet alone, (a fourth and a third, respectively), based on our currently population, that would be over 1.7 billion people killed within the first 3 1/2 years and that is not including the fatalities that will result from trumpets 1, 2 and 3, nor the results from the seven bowl judgments. Most people don't go any deeper than a cursory reading. Allow me to demonstrate:
First Trumpet
"The first angel sounded his trumpet, and there came hail and fire mixed with blood, and it was hurled down on the earth. A third of the earth was burned up, a third of the trees were burned up, and all the green grass was burned up."
If you have a third of the earth and trees burned up, how many people will be caught in that third? For those who are post-trib, not that He couldn't, but is God going to make sure that the no one belonging to the church is within that third? Remeber, the ocean is not included in that. That's a lot of area and a lot of people.
Second Trumpet
"The second angel sounded his trumpet, and something like a huge mountain, all ablaze, was thrown into the sea. A third of the sea turned into blood, a third of the living creatures in the sea died, and a third of the ships were destroyed."
This sounds like John is describing an asteroid coming through the earths atmosphere, which is why it would look like huge mountain and why is was all ablaze. Whatever the object is, it hits in one of the oceans which creates giant Tsunami's, which is why a third of all of the ships in that body of water are destroyed, which equal a third over all the earth. This would include, military ships, cruise liners, pleasure craft, oil tankers, etc. This would affect every type of ship whether out at sea, docked, or inbetween. Any ship that is caught in that body of water will be destroyed. To be more descriptive, what if say, the body of water was the Atlantic. Every sea creature and ship would be killed and destroyed equaling a third over all the earth.
How many people on those ships?
How many people will be living on the coasts of every shore touching that body of water when those Tsunami's hit?
Depending on how big, how fast and at what angle that object hits, will determine the size of the waves. How far inland will those 1000 plus foot waves go? This is what I mean when I tell people to look deeper into these plagues of wrath. If it was to hit in the Atlantic, you'd be talking about every city along the east coast of the United states, south America, Canada, Finland, as well as the west coast of Scotland, Ireland, Spain, Portugal and the entire west coast of Africa. I'm just setting the scene here.
Not that He couldn't, but is God also going to make sure that there will be no believers of the church living or present on any of those coastlines when it hits?
Once again, you see how ridiculous that is, for God to shift believers around the planet so that they are not on that third part of the earth or those trees that get burnt up and to make sure that there are no believers within the church living on any of those coastlines where those Tsunami's hit and also that there are no believers on any of the ships.
Wouldn't it be better to just remove the church from the earth as promised, so that the church is not even exposed God's wrath?
Third Trumpet
"The third angel sounded his trumpet, and a great star, blazing like a torch, fell from the sky on a third of the rivers and on the springs of water—the name of the star is Wormwood. A third of the waters turned bitter, and many people died from the waters that had become bitter."
This object sounds to me like a comet hitting the atmosphere and exploding. Comets are made of debris and ice. While they are orbiting our sun, they are absorbing all types of radiation and retaining it. If a comet exploded in our atmosphere, all of that ice that has been absorbing all that radiation, would fall all over the earth, contaminating our rivers and fresh water, which is why the scripture says that many people die from drinking the water.
How many is many?
Since this is going to be contaminating a third of the rivers and springs of water, needless to say, that would affect a lot of people. They would die from the inside out from drinking radioactive water.
And these post-tribbers think that God, instead of catching up the church, is instead going to leave them on the earth to go through all of that. I'll do one more from the bowl judgments:
Fourth Bowl
"The fourth angel poured out his bowl on the sun, and the sun was allowed to scorch people with fire. They were seared by the intense heat and they cursed the name of God, who had control over these plagues, but they refused to repent and glorify him."
This plague will allow the sun to scorch people with fire and sear them with intense heat! Where on earth can you go, except a cave to escape from that? And how long will that scorching heat last? How would God protect the church to keep them from the sun? How many are going to die from that excessive scorching heat? Not to mention, that in the previous bowls all of the ocean and fresh water will have been turned into literal blood. No drinking water, but lots of scorching heat!
This is why I always say that post-trib people need to do a deeper study of the seals, trumpets and bowl judgments. It is just ridiculous to believe that God is going to protect His church during the time of these plagues of wrath, instead of gathering them from off the earth according to His promise.
Ok, I'm done ranting!