2t2 comes after 2T1 where Paul describes what is clearly the coming of the Lord Jesus for judgment of the wicked & glorification of the persecuted saints.
2T1:5 All this is evidence that God’s judgment is right, and as a result you will be counted worthy of the kingdom of God, for which you are suffering. 6 God is just: he will pay back trouble to those who trouble you 7 and give relief to you who are troubled, and to us as well. This will happen when the Lord Jesus is revealed from heaven in blazing fire with his powerful angels. 8 He will punish those who do not know God and do not obey the gospel of our Lord Jesus. 9 They will be punished with everlasting destruction and shut out from the presence of the Lord and from the glory of his might 10 on the day he comes to be glorified in his holy people and to be marvelled at among all those who have believed. This includes you, because you believed our testimony to you.
Paul teaches that certain events must happen
before that final day of the Lord:
2T2:3 Don’t let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness is revealed, the man doomed to destruction. 4 He will oppose and will exalt himself over everything that is called God or is worshipped, so that he sets himself up in God’s temple, proclaiming himself to be God.
Now, as far as the Ts were concerned:
some had died (see 1T4) and Paul had assured them that they would not miss out on blessing.
1T4:13 But I do not want you to be ignorant, brethren, concerning those who have fallen asleep, lest you sorrow as others who have no hope. 14 For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus
They were asleep in Jesus & when Jesus comes for resurrection, living & dead will be glorified, &
ever with the Lord.
He had also told them that that Jesus' Olivet prophecy would be fulfilled to the uttermost:
1T2:14 For you, brethren, became imitators of the churches of God which are in Judea in Christ Jesus. For you also suffered the same things from your own countrymen, just as they did from the Judeans, 15 who killed both the Lord Jesus and their own prophets, and have persecuted us; and they do not please God and are contrary to all men, 16 forbidding us to speak to the Gentiles that they may be saved, so as always to fill up the measure of their sins; but wrath has come upon them to the uttermost.
But in 2T1 they were still suffering persecution & no sign of Jesus coming to judge the unbelieving Jews.
Also Peter had to remind his readers:
2P3:1 Beloved, I now write to you this second epistle (in both of which I stir up your pure minds by way of reminder), 2 that you 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 Savior, 3 knowing this first: that scoffers will come in the last days, walking according to their own lusts, 4 and saying, “Where is the promise of His coming?
In Hebrews 3 & 4 we read the warning that the Jews had 40 years to enter God's rest, or would suffer God's wrath for their unbelief.
God is gracious & longsuffering, but his patience will come to an end. The Jews will NOT be allowed to continue mocking Jesus & his warnings, warnings repeated by the Apostles.
Jesus coming to judge
this generation that rejected him would certainly take place as prophesied. John repeats Jesus' prophecy against those
who pierced Him in Rev. 1:7. But, not only had some of the Thes. believers died, it is likely that some of the Jewish leaders had also died. Herod had had his own private judgment. (Acts 12:20-23)
Jesus had given clear signs concerning the destruction in his Olivet prophecy. Paul by inspiration adds to those signs in 2T2.