2 Thessalonians opens as most letters do, the who from and who to stuff and a general good tidings of grace and peace. There is good news on the outset, as the Thessalonians are growing in faith and love for one another, things that Paul asked them to focus on previously. In fact, the bros share about the Thess. church to the other churches they go to, specifically because of their steadfastness in the face of persecution and affliction (which, of course, Paul is familiar with as well.)
v.6 reads a bit odd so it’s important to keep it in context. Basically Paul is saying that their steadfastness if evidence that God has judged rightly in saving them and granting them citizenship in the Kingdom (obviously facilitated by Jesus). This is known with certainty, their actions are evidence of their faith, as they are doing what Jesus did, persisting through persecution for the glory of God and the benefit of others. On the opposite side, those who are doing the afflicting will ultimately receive just punishment as they both reject the work of Jesus and persecute those who continue it.
Ultimately, all will be set right when “the Lord is revealed from heaven with his might angels in flaming fire inflicting vengeance on those who do not know God and on those who do not obey the gospel of our Lord Jesus.” A few things to be careful of here. For starters, there are hints here of Isaiah 64 and 66 so it’s likely these are big, final claims as opposed to something to be happening directly. Also, the word for “revealed” is apokalypsis, where we get the word apocalypse, also used in Revelation 1. It means to be uncovered (think “shown”) so we shouldn’t think of “revealed from heaven” as a directional thing, more of “when what has previously been hidden is now revealed” type of thing. Also, 2 Samuel 22 and the Psalms describe God as the one who avenges his people from their enemies.
Those on the outside will suffer the punishment of eternal destruction, away from the presence of the Lord. This is a pretty simple principle, really. Folks who reject Jesus and do not want to submit to God will ultimately get what they want, eternal separation from Him. It’s a terrible decision, but it is their decision. On the other hand, Jesus and his glory is ultimately revealed through, to and by his people. And that is what Paul and the bros are praying for, that God will provide the means and ways to fulfill the calling He has given them that their actions may reveal their worthiness. And it is indeed a high calling, to be worthy of having people know Jesus through you, his glory revealed in the work He has you up to.
This is a common theme here but it applies to us as well. As Christians (literally “little Christs”), Jesus is revealed to the world through his people. That’s us. That’s a high calling and it extends to each one of us. You matter, God has Kingdom work for you to do, get up each morning with a mind and heart to do it.