What makes us certain that Mat 25 somehow means that the final judgment is not after the 1000 years?
What? I don't understand your question.
Either it refers to that, or there is also a judgment from Jesus at His return. In either case that has nothing to do with there being no 1000 years!
Matthew 25:31-46 clearly occurs at His return because it talks about Him coming with His angels. So, if that's the final judgment then what does that tell you about the timing of the thousand years in relation to His return?
I am not familiar with those terms. I think that means Jesus first returns and then rules for 1000 years? If so, yes, of course that is what the bible says.
Premillennialism is the belief that the thousand years occurs after Jesus returns. Amillennialism is the belief that the thousand years is an actual period of time but that the word "thousand" is figurative and represents the time period that began with Christ's resurrection since that is when He began to reign (Matthew 28:18, Ephesians 1:19-22). And that time period lasts up until Satan's little season which Amillennialism sees as occurring just before the second coming of Christ.
2 Peter 3:7
But the heavens and the earth, which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of ungodly men.
That is after the 1000 years as we know from other places in the bible.
And in the following verse in that chapter it is also talking of the same thing.
2 Peter 3:10
But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
That is after the milennium. Not when Jesus returns to rule and lands on the mount of Olives. That means that the period called the day of the Lord is not one single minute or hour or day. It has to be a period of time. In that day (at the end of it) after the 1000 years, the earth is burned and made new.
Where is there any indication in 2 Peter 3 that the day of the Lord is a period of time longer than a day?
The context of 2 Peter 3:3-13 is established in verses 3 and 4.
3 Knowing this first, that
there shall come in the last days scoffers, walking after their own lusts, 4 And saying, Where is the promise of his coming? for since the fathers fell asleep, all things continue as they were from the beginning of the creation.
Notice that it talks about scoffers scoffing at the promise of His second coming. They think He should have come already if He was going to come, but they are ignorant.
Keeping in mind that Peter is talking about the second coming of Christ in 2 Peter 3:3-4, he then wrote this:
5 For this they willingly are ignorant of, that by the word of God the heavens were of old, and the earth standing out of the water and in the water: 6 Whereby the world that then was, being overflowed with water, perished: 7 But the heavens and the earth, which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of ungodly men.
Peter indicated that these last days scoffers are ignorant of the global flood that occurred long ago. And then he indicated that "the heavens and the earth, which are now, by the same word are kept in store, reserved unto fire". So, he was talking about another destruction event that he compared directly in scope to the global flood, except this time the global destruction will occur by way of fire instead of water. And, again, this is in relation to the second coming of Christ. He didn't change the subject that he established in verses 3 and 4 in verse 5.
Then in verses 8 and 9 he explains that the Lord is not being slow concerning the fulfillment of the promise of His coming as some, like those last days scoffers, might think, because time is irrelevant to the Lord.
Then he wrote this:
2 Peter 3:10
But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up. 11 Seeing then that
all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness, 12 Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat? 13
Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.
Peter did not change the subject in verse 10. Starting in verse 3, the context is all about the second coming of Christ and things that would relate to the fulfillment of the promise of His coming. So, the day of the Lord is not some period of time like you think, it is the day that Jesus will return. On that day the heavens and earth will be burned up, as Peter indicated.
There's no basis for thinking that will happen 1000+ years after Christ returns. Peter gave no such indication of that at all. Instead, he told his readers that it was important for them to be careful about what they talked about and about living godly lives in anticipation of the arrival of the day of the Lord. Why would Peter say that to his readers if he was talking about something that wouldn't even happen until 1000+ years after the return of Christ? That would make no sense.
That Christ would burn up the heavens and the earth when He returns, which obviously would destroy all of the wicked, lines up perfectly with what Jesus Himself said will happen when He comes.
Matthew 24:35
Heaven and earth shall pass away, but my words shall not pass away. 36 But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only. 37 But as the days of Noah were, so shall also the coming of the Son of man be. 38 For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until
the day that Noe entered into the ark, 39 And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be.
Jesus associated heaven and earth passing away with His second coming and He indicated that just as the flood destroyed all of the wicked in Noah's day, "so shall also the coming of the Son of man be". The wicked will all be destroyed when He comes as well. Which makes sense since the entire earth will be burned up.
Notice in 2 Peter 3:13 that Peter indicates that "we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness". That means the ushering in of the new heavens and new earth is "according to his promise". What promise? The promise of His second coming (2 Peter 3:4). So, that places the timing of the ushering in of the new heavens and new earth at His second coming and not 1000+ years later.
Great, so we get no rewards in that judgment in heaven?
What judgment in heaven? Tell me what scripture talks about some judgment occurring in heaven.
Jesus does not take over the world when He returns, destroying all enemies? (that is a judgment)
Sure, He does, but He will deliver His kingdom, which does not come with observation and is not of this world, to the Father at that point (1 Corinthians 15:22-24).
Matthew 12:36 But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.
That seems to be that final judgment day when the dead are raised to be judged. Of course that is not the saved dead. That is after the 1000 years as the bible says.
So, the day of judgment Jesus mentioned there is somehow a different day of judgment than John wrote about in the following verse?
1 John 4:17 Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world.
That could be talking about when He returns to rule, and/or in the days before when the world is being judged in wrath. In those days we need boldness (those believers that are left and alive then). When He judges the wicked at the end in the final great judgment, why would we need to be bold then?
We all have to stand before Christ to give an account of ourselves (Romans 14:10-12), so it has to do with having boldness when giving an account of ourselves. We don't want to be ashamed when we stand before Him, we want to have the confidence that we can give an account of ourselves without being ashamed of ourselves.
Matthew 25:31-46 is very clear that both the saved and the lost will stand before Him when He comes and will be judged at the same time. The idea of multiple judgment days is simply not taught in scripture.
There is the seat of Christ when rewards are handed out after the Marriage Supper. Does that count? There is Jesus wiping out all enemies when He returns, does that count? If not, then all that is left is that great final judgment.
That will all happen when He returns. He is not going to descend from heaven twice in the future as you apparently believe. That is not taught anywhere in scripture.