I am writing this letter to you in order to help you remember what the holy prophets said and what our Lord and Savior commanded.
2 Peter 3:1-2
This letter that I am now writing to you whom I love, is the second letter that I have written to you. In both these letters I have reminded you about the things you already know, in order that I may stimulate/cause you to think sincerely about those things. I want you to remember the words that were spoken by the holy prophets {that the holy prophets spoke} long ago, and also to remember what our Lord and Savior commanded, things that we, your apostles, told you about.
Although certain people will ridicule the idea that the Lord Jesus Christ is going to come back, the reason why he has not yet come back to judge people is that God is being patient with people; but Jesus will certainly come back and judge people.
2 Peter 3:3-10
It is important for you to understand that in the time immediately before Christ comes back, there will be people who will ridicule the idea of his coming back. Those people will do whatever evil things they wish to do. They will say, “Although it was promised that Christ will come back, ◄nothing has happened that would indicate that he is coming back./what happened to the promise that he is coming back?► [RHQ] We say that because ever since the Christian leaders who lived long ago died [EUP], everything has remained the same. Things are as they always have been since God created the world! They will say that because they ◄deliberately overlook the fact/have decided to ignore what they know► that God, by commanding long ago that it should be so, caused the heavens to exist, and he caused the earth to appear out of water and to be separate from the water. And God, by commanding that it should be so, later destroyed the world that existed at that time, by causing the earth to be flooded with water {water to flood the earth}. Furthermore, God, commanded that the heavens and the earth that exist now remain until the time when he will judge ◄ungodly people/people whose lives are not pleasing to him►. And at that time he will destroy the heavens and the earth by burning them. Dear friends, I want you to understand well that the Lord God is willing to wait a long time to judge the people in the world! How much time passes before the Lord God judges the people in the world does not matter to him! He considers that one day passes no more quickly than 1,000 years, and he also considers that 1,000 years pass as quickly as one day passes to us! Therefore, you should not think that because Christ has not yet come back to judge people, the Lord God is ◄delaying/slow to do► what he promised. Some people think that this is so, and they say that Christ will never come back. But you should understand that the reason why Christ has not yet come back to judge people is that God is being patient with you, because he does not want anyone to be lost eternally. Instead, he wants everyone to turn away from their sinful behavior. 10 Although God is being patient, at the time [MTY] that he has chosen, the Lord Jesus Christ will certainly come back to judge people. He will come back unexpectedly, like a thief [SIM] comes unexpectedly. At that time there will be a great roaring sound. The heavens will cease to exist. ◄The elements/The parts of which the universe consists► will be destroyed by fire, and the earth that God made and everything on it that people have made will disappear (OR, will be burned up).
You certainly ought to behave in a godly manner, because God will destroy everything, and because only those people who are righteous will live in the new heavens and on the new earth.
2 Peter 3:11-13
11 Because God will certainly destroy all these things like I just said, you certainly know how you should behave. [RHQ] You should behave ◄in a godly manner/in a manner that pleases God12 while you eagerly/expectantly wait for Christ to return on the day that God has chosen [MTY], and you should try to make that day come soon. Because of what God [PRS] will do on that day, the heavens will be destroyed. ◄The elements/The parts of which the universe consist► will melt and burn up. 13 Although all those events/things will happen, we rejoice because we are waiting for the new heavens and new earth that God has promised. The only people who will be in the new heavens and on this new earth will be people who are [PRS] righteous.
Do all you can to conduct your lives in a godly manner. Guard against those who would entice you to doubt what you now firmly believe.
2 Peter 3:14-18a
14 Therefore, dear friends, because you are waiting for these things to happen, do all that you can live ◄in a godly manner/in a manner that pleases God►, in order that Christ will see that you are completely pure [DOU] and that you are living peacefully with each other. 15 And think about this: Our Lord Jesus Christ is patient because he wants people to be saved. Our dear ◄brother/fellow believer► Paul also wrote wise words to you about these same matters, because God enabled him to understand theseevents/things that will happen►. 16 In the letters that Paul wrote there are certain things that are difficult for people to understand. People who are spiritually ignorant and ◄unstable/do not believe firmly in Christ► interpret these things wrongly, as they also ◄interpret/explain the meaning of► the other parts of the Scriptures wrongly. The result is that they will destroy themselves spiritually, and God will punish them. 17 Therefore, dear friends, since you already know about those who teach what is false, ◄guard against them/beware►. Do not let those wicked people deceive you by telling you things that are wrong, with the result that you yourselves begin to doubt what you now firmly believe. 18  Instead, live in such a manner that you experience more and more our Savior Jesus Christ being kind to you, and that you get to know him better and better.
I pray that Jesus Christ will always be honored.
2 Peter 3:18b
I pray/desire that Jesus Christ will be honored both now and forever!* Amen./So be it. At the end.

*3:18 Amen./So be it. At the end.