What God gave His prophets to write about the coming end of this earth age, the New Testament writers also continued. That doesn't mean it was fulfilled in their days, nor the days of the OT prophets. This is why Apostle Peter told us to be mindful of what God's Old Testament prophets were given to write. The reason is because a lot of events written in the OT prophets has still not happenned even today.
2 Pet 3:1-14
1 This second epistle, beloved, I now write unto you; in both which I stir up your pure minds by way of remembrance:
2 That ye may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us the apostles of the Lord and Saviour:
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."
Apostle Peter reveals a certain deception by some in the last days concerning what the OT prophets were given to write about the end of this earth age we've been in (Isaiah 24 & 25 would make a good study on some events yet to come today compared to Peter's Message here). Peter shows there would come scoffers in the last days, mocking the idea of Christ's literal second coming and declaring the creation continuing like it has.
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:
These "scoffers" Peter says, are "willingly ignorant" of the events when God first established His creation of old, and then by it being overflowed by water, it perished. It's not a small thing to want to be ignorant of that fact. No mystery then, that those scoffers also choose to treat those literal events that happened like it was some fairy tale, or some literary device, like God's Word is not about His Truth, but like some man's book of poetry or philosophy.
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.
The "scoffers" are "willingly ignorant" when God brought waters of a flood upon this earth long ago. They also are willingly ignorant of this coming destruction of this present earth age by fire in the future.
8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
9 The Lord is not slack concerning His promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.
The very reason why this present earth age has been allowed to last so long, before the time of God's destruction of it by fire in our future, is that our Heavenly Father is long-suffering toward us, not wanting any soul to perish, but that we ALL would come to repentance. Our lack of patience can't be compared to His great patience with all the evils going on in today's world.
Nevertheless, like His promise, He has said He will indeed one day bring the destruction of this present earth age we're still in today, "the heavens and the earth, which are now".
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.
Our Heavenly Father first gave this promise of the destruction of "the heavens and the earth, which are now" back in the Old Testament prophets. That's why Peter admonished us Christians to be mindful of what God's holy prophets had written. They covered this coming event, which is still future to us. And here Peter is covering it again in the New Testament.
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?
So what manner of conversation are we Christians to have concerning that coming event? Are we to be "willingly ignorant" of it like the "scoffers"? No. We are to always keep that coming event in our minds and hearts to know it is coming, because for those in Christ Jesus that event is about His return to this earth and our gathering to Him, The Salvation He promised us which is to have real substance, and not just a spiritual state of mind, but real peace on earth in His de facto Presence ruling over all the earth.
13 Nevertheless we, according to His promise, look for new heavens and a new earth, wherein dwelleth righteousness.
14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of Him in peace, without spot, and blameless.
(KJV)
We know we aren't in that "new heavens and a new earth" time yet. But we are to wait for it, because The LORD promised it to His servants in Christ Jesus. And we are not to be "willingly ignorant" of these literal changes that God has worked on this earth before, and will yet once more, this last time being a destruction by His consuming fire (see end of Hebrews 12 also).
.
2 Pet 3:1-14
1 This second epistle, beloved, I now write unto you; in both which I stir up your pure minds by way of remembrance:
2 That ye may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us the apostles of the Lord and Saviour:
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."
Apostle Peter reveals a certain deception by some in the last days concerning what the OT prophets were given to write about the end of this earth age we've been in (Isaiah 24 & 25 would make a good study on some events yet to come today compared to Peter's Message here). Peter shows there would come scoffers in the last days, mocking the idea of Christ's literal second coming and declaring the creation continuing like it has.
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:
These "scoffers" Peter says, are "willingly ignorant" of the events when God first established His creation of old, and then by it being overflowed by water, it perished. It's not a small thing to want to be ignorant of that fact. No mystery then, that those scoffers also choose to treat those literal events that happened like it was some fairy tale, or some literary device, like God's Word is not about His Truth, but like some man's book of poetry or philosophy.
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.
The "scoffers" are "willingly ignorant" when God brought waters of a flood upon this earth long ago. They also are willingly ignorant of this coming destruction of this present earth age by fire in the future.
8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
9 The Lord is not slack concerning His promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.
The very reason why this present earth age has been allowed to last so long, before the time of God's destruction of it by fire in our future, is that our Heavenly Father is long-suffering toward us, not wanting any soul to perish, but that we ALL would come to repentance. Our lack of patience can't be compared to His great patience with all the evils going on in today's world.
Nevertheless, like His promise, He has said He will indeed one day bring the destruction of this present earth age we're still in today, "the heavens and the earth, which are now".
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.
Our Heavenly Father first gave this promise of the destruction of "the heavens and the earth, which are now" back in the Old Testament prophets. That's why Peter admonished us Christians to be mindful of what God's holy prophets had written. They covered this coming event, which is still future to us. And here Peter is covering it again in the New Testament.
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?
So what manner of conversation are we Christians to have concerning that coming event? Are we to be "willingly ignorant" of it like the "scoffers"? No. We are to always keep that coming event in our minds and hearts to know it is coming, because for those in Christ Jesus that event is about His return to this earth and our gathering to Him, The Salvation He promised us which is to have real substance, and not just a spiritual state of mind, but real peace on earth in His de facto Presence ruling over all the earth.
13 Nevertheless we, according to His promise, look for new heavens and a new earth, wherein dwelleth righteousness.
14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of Him in peace, without spot, and blameless.
(KJV)
We know we aren't in that "new heavens and a new earth" time yet. But we are to wait for it, because The LORD promised it to His servants in Christ Jesus. And we are not to be "willingly ignorant" of these literal changes that God has worked on this earth before, and will yet once more, this last time being a destruction by His consuming fire (see end of Hebrews 12 also).
.