Is this verse speaking of the rapture or about when heaven and earth pass away (which is mentioned in the preceding verse)?
There are some scriptures that indicate that we may know the date of the rapture and that it will not overtake us like a thief.
Can we know the day of the rapture?
So believers are called to be ever watchful for the day of His coming. This is really important. But we are watchful, as the 1st Century Galilean bride was, because we (like her) do not know the day. We can see that the day is approaching and close. It is amazing to see. But scripture never teaches that we can know the day. And this is exactly how it should be.
Not knowing, but always desiring, makes a person ever watchful for that day.
Dan 12:4 But you, Daniel, close up and seal the words of the scroll until the time of the end. Many will go here and there to increase knowledge."
This is a general prophecy about knowledge increasing in the last days. It will. It has. There are prophecies that have and are becoming clearer to us in these days. But it doesn't say anything about the fact that we will know the day of Jesus return which Jesus Himself, in multiple passages, said we would not.
Mat 24:50 The master of that servant will come on a day when he does not expect him and at an hour he is not aware of.
The argument goes that it is the wicked servant that will not be aware of the day Jesus returns, but faithful servants will. This however is missing the point. The parable doesn't say or teach that the good servant knows the day in advance but the emphasis is on being found faithful, ready and watchful when He does come. The point is that the master is going away and His servants don't know when He will return. One, though He doesn't know the day, is watchful for His master's return. The other doesn't care and starts acting wickedly. Though neither knows the day of their masters return, the first will be ready and the second won't.
|1 Thess 5:4
1Th 5:4-5 But you, brothers, are not in darkness so that this day should surprise you like a thief. You are all sons of the light and sons of the day. We do not belong to the night or to the darkness.
This is used because it says this day should not overtake you like a thief. Which it won't. But this is not speaking of the day of the rapture but the 'day of the Lord' which is the period of God's wrath upon the world in the coming tribulation. Paul is saying that we are not of that day. The church won't be overtaken by that day of darkness (the tribulation) because we are not of that day. The Lord will return and receive us to Himself before that day. But again, this verse is not saying that we can know the day of Jesus return. It is about the day of the Lord.
Heb 10:25 Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another--and all the more as you see the Day approaching.
This is used because it says 'and all the more as you see the day approaching'. And we should know and see that the day is approaching. This is a general knowing of the season and closeness of His return. It is not knowing the actual day of His return. To give an illustration, if you had a elderly loved one who was approaching their end, you would see the signs and know that the day of their passing is approaching. But the actual day is still unknown. Will they last 1 more day? 1 week? A month? More? Only God knows. All we can say is that the day is approaching. So it is with the rapture. The signs tell us that it is close but we know not the exact day.
Rev 3:3 Remember, therefore, what you have received and heard; obey it, and repent. But if you do not wake up, I will come like a thief, and you will not know at what time I will come to you.
This is used because it says 'But if you do not wake up, I will come like a thief, and you will not know at what time I will come to you.' The argument is that it is the unfaithful church that won't know the time that Jesus comes. Firstly, I don't actually think this is even about the Lord's return. It was a warning that if this church didn't repent Jesus would come to them unexpectedly (like a thief) in judgement. It is very similar to what Jesus said to the church in Ephesus:
Rev 2:5 Remember the height from which you have fallen! Repent and do the things you did at first. If you do not repent, I will come to you and remove your lampstand from its place.
While I don't believe it is, even if you took it as the rapture, all it is saying is that some unfaithful believers will be caught unawares at the Lord's coming. Jesus' coming isn't like a thief for those that are faithful because they are watching. But again, we are instructed to watch, according to Jesus, because we do not know the day of His return.