1 Now concerning the return of our Lord Jesus Christ, and our being gathered to Him, brothers,
2 we request that you people do not become shaken up in your mind, nor alarmed, either by a spirit [i.e., by some prophetic prediction], or by a report, or by a letter supposedly from us, that the day of the Lord [i.e., when Jesus returns] has already come.
3 Do not allow anyone to deceive you in any way, for it will not occur until the rebellion comes first and the man of lawlessness becomes evident. [Note: This "rebellion" refers to a significant falling away from the teaching and practice of true Christianity (See I Tim. 4:1), characterized by the rise of an authoritarian religious leader]. This man is doomed to be destroyed
4 [for] he opposes [the true Gospel message] and exalts himself against everything that is called "God" or that which is worshiped. So, he sits in God's temple [i.e., the church ?] displaying himself as [though he were] God.
5 Do you not remember that I used to tell you these things when I was still with you?
6 [But] for now, there is something holding him back [i.e., holding back the man of lawlessness from emerging, See verses 3-4], and you people know what it is. [It is restraining him] so that he will not be revealed until his own [due] time.
7 For this mysterious lawlessness is already at work [or, "this lawlessness is already secretly at work"]; but the one who is holding it back [will continue to do so] until he is removed.
8 And then the lawless person [See verse 3] will be revealed, the one whom the Lord Jesus will destroy with the breath of His mouth and bring to an end by the brilliant appearance of His presence [i.e., at His second coming].
9 The coming [of this lawless person] is according to the work of Satan, [and will be] attended by all kinds of powerful [i.e., miraculous] signs and false wonders,
10 and all kinds of wicked deception toward those people who are perishing [spiritually], because they refused to love the truth so they could be saved.
11 And this is the reason that God sends them a strong delusion [to influence them]: It is so that they would believe the lie,
12 in order that all those who have not believed the truth, but have taken pleasure in wrongdoing, would be condemned.
13 But we ought to thank God for you always, brothers [who are] dearly loved by the Lord, because God has chosen you from the beginning [Note: Some manuscripts use the Greek word for "firstfruits" instead of "beginning" here, but it is difficult to know in what sense the Thessalonian Christians were "first"], in order to be saved through being set apart by the Holy Spirit and through belief of the truth [of the Gospel].
14 He called you [to this salvation] through our Gospel message, in order that you could obtain the splendor of our Lord Jesus Christ [in heaven].
15 So then, brothers, stand firm [in the faith], and hold onto the [inspired] traditions which you were taught, whether by word [of mouth] or by a letter from us.