At the end of this aeon, when this age is ended and the eon to come begins, unbelievers will be taken away and believers will remain on earth and enter the Kingdom. But unlike the great tribulation, it is unknown how long this period will last and when exactly the end of this aeon will be.
42 Watch therefore, for you have not perceived what day your Lord is coming.
vigilant
Then watch! is concluding in response to the foregoing. Because it is not known exactly when the future aeon will begin, here is the call for vigilance. The one who watches stands firm in the faith (1 Cor.16:13). They do not sleep, but are awake and live by the light of the word of God (1 Thess.5:6). That is why they do not allow themselves to be lulled to sleep by what ‘people’ say (1 Thess.5:3), but they are sober, sensible (1 Pet.5:8), steadfast (Rev.3:2) and endure. Earlier we saw that with regard to the end of the aeon it was said: But whoever endures until the end will be saved (:13).
presence and arrival
In the parousia (>presence) of the Son of man, it will be as in the days of Noah. The Lord is present with His people in the wilderness at Bozrah, where Israel is gathered, and He is their King. The end of the aeon is near, but people will generally not be aware of this. Until the Lord comes and then the unbelievers will be judged.
the throne of His glory
The word translated as coming (erchomai) in verse 42 is a different word than parousia, which in current translations is also translated as (future) coming, but literally speaks of His presence. His coming here concerns the moment when the Lord will sit on the throne of His glory (Matt.25:30). Then He will establish His kingdom over all the earth and He will judge the nations (Matt.25:31).
43 But know this: If the owner of the house had known in what watch the thief would come, he would have watched, and never suffered his house to be broken up.
Jesus compares His coming to the coming of a thief. If the homeowner had known in which night’s watch the thief would come, he would have kept watch. Apparently this homeowner is not vigilant (:42) and doesn’t know. If he had known, he wouldn’t have allowed himself to be robbed. But the idea is that he should have known.
the book of Daniel sealed until the end time
One can know at that time that the end of the aeon is near. Not exactly to the day and hour (:36, 42, 44), but that one lives in the period in which it will happen.
In Daniel it says that the book is closed and sealed until the time of the end (Dan.12:4,9). In the time of the end there will be those who are wise (>Hebrew: maskilim) and they will understand the book of Daniel (Dan.12:10). Many will inquire and knowledge will increase (Dan.12:4). Would this also be true with regard to the end of the aeon? Now the day and time are not known, but then the time may become clear.
thief
Just as in Matthew 24:43, we often find a comparison with a thief regarding the coming of the Lord. When Paul speaks of the times and occasions of the snatching away (1 Thess. 4:13-1 Thess. 5:1), he says:
2 For you yourselves know exactly that the day of the Lord is coming like a thief in the night.
3 For whenever they say, ‘Peace and security’, then suddenly a complete collapse will come, like the travail of a pregnant woman, and they will not escape.
4 But you, brothers, are not in darkness, lest the day seize you like a thief…
To those who live in darkness, the Lord comes like a thief in the night. However, not for those who are vigilant. That day will not overtake them, because they live by the light of the word and are vigilant (1 Thess.5:3-6).
similarities and differences
Although the snatching away is an event that occurs several years before the time described in Matthew 24:42-44, the principle is the same. We do not know how long the peace and security described will last, but when it does, we know that the moment of the snatching away is at hand.
So it is with regard to the end of the aeon. Although no one knows that day and hour (Matt. 24:36), one can know from events that the moment is at hand. After the restoration of Israel, summer would arrive within a generation (Matt.24:32-34), the beginning of the aeon to come.
In both cases the Lord comes upon the unbelievers, who sleep and are not awake, like a thief, unawares. It also applies to both that for the believers that day will not come like a thief. They are alert and sons of light.
In both cases the Lord also comes to take something away, just like a thief. He takes it away from a house ruled by another. The god of this aeon (2 Cor. 4:4) reigns in this present evil aeon (Gal. 1:4). The difference is that in the snatching away, unlike a thief, the Lord takes away what belongs to Him. At the end of the aeon, he takes away the disbelievers.