The return of Christ in flaming fire coming down on the wicked from God out of Heaven.
Someday God will say to the Son, it is time and God will send us Christ again.
The first time Christ came was for sin, the second time for our salvation, (Hebrews 9:28), a salvation ready to be revealed in the last time is what Peter says. A salvation that is deliverance from the evil of that time. It will be worse than the time that Noah experienced.
Christ's return means our salvation and for the unbelieving world certain destruction of God's wrath on them. And the people of that time are also fully sold out to Satan, it is not like they are good people. They are under a strong delusion from God because they refused to love the truth and be saved, so they knew. So they believe the LIE...
Now, brethren, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we ask you, 2 not to be soon shaken in mind or troubled, either by spirit or by word or by letter, as if from us, as though the day of [
a]Christ had come. 3 Let no one deceive you by any means; for
that Day will not come unless the falling away comes first, and the man of [
b]sin is revealed, the son of perdition, 4 who opposes and exalts himself above all that is called God or that is worshiped, so that he sits [
c]as God in the temple of God, showing himself that he is God.
5 Do you not remember that when I was still with you I told you these things? 6 And now you know what is restraining, that he may be revealed in his own time. 7
For the [d]mystery of lawlessness is already at work; only [e]He who now restrains will do so until He is taken out of the way. 8 And then the lawless one will be revealed, whom the Lord will consume with the breath of His mouth and destroy with the brightness of His coming. 9 The coming of the lawless one is according to the working of Satan, with all power, signs, and lying wonders, 10 and with all unrighteous deception among those who perish, because they did not receive the love of the truth, that they might be saved. 11 And for this reason God will send them strong delusion, that they should believe the lie, 12 that they all may be condemned who did not believe the truth but had pleasure in unrighteousness.
Stand Fast
13
But we are [f]bound to give thanks to God always for you, brethren beloved by the Lord, because God from the beginning chose you for salvation through [g]sanctification by the Spirit and belief in the truth,
14 to which He called you by our gospel, for the obtaining of the glory of our Lord Jesus Christ.
15 Therefore, brethren, stand fast and hold the traditions which you were taught, whether by word or our [h]epistle.
16 Now may our Lord Jesus Christ Himself, and our God and Father, who has loved us and given
us everlasting consolation and good hope by grace, 17 comfort your hearts and [
i]establish you in every good word and work.
Satan's restrainer is the angel (Michael), who locked him up in that pit. Satan gets released at the end and works all this terrible wrath on the whole world through his one world government of evil over the nations. If Satan could do that today, he certainly would, but he is prevented, as in restrained in a spiritual imprisonment.
v13 explains how because of the love God has for His elect whom he chose, we are saved by the gospel of Christ, as God granted US to know Him. And that from before time began, we were chosen in Him.
Ephesians 1
1 Paul, an apostle of Jesus Christ by the will of God,
To the saints who are in Ephesus, and faithful in Christ Jesus:
2 Grace to you and peace from God our Father and the Lord Jesus Christ.
Redemption in Christ
3 Blessed
be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly
places in Christ, 4
just as He chose us in Him before the foundation of the world, that we should be holy and without blame before Him in love, 5 having predestined us to adoption as sons by Jesus Christ to Himself, according to the good pleasure of His will, 6 to the praise of the glory of His grace, by which He [a]made us accepted in the Beloved.
7 In Him we have redemption through His blood, the forgiveness of sins, according to the riches of His grace 8 which He made to abound toward us in all wisdom and [
b]prudence, 9 having made known to us the mystery of His will, according to His good pleasure which He purposed in Himself, 10 that in the dispensation of the fullness of the times He might gather together in one all things in Christ, [
c]both which are in heaven and which are on earth—in Him. 11 In Him also we have obtained an inheritance, being predestined according to the purpose of Him who works all things according to the counsel of His will, 12 that we who first trusted in Christ should be to the praise of His glory.