Shared ground
Paul treats the Thessalonians’ ongoing suffering as meaningful, not random. Explicitly, he calls it an “obvious sign” that God’s judgment is fair (v.5). He also explicitly connects their suffering to “the kingdom of God” (v.5): they suffer in relation to belonging to, and being aligned with, that kingdom.
Paul then explains what “fair” looks like in God’s future response. Explicitly, God will repay trouble to those who are troubling them (v.6), and explicitly, God will give relief to the afflicted (v.7), including Paul and his coworkers (“with us”). The timing of that relief is linked to Jesus’ public revealing “from heaven” with powerful angelic attendants and fiery imagery (v.7).
Where interpretation differs
What “this” is in v.5. Some read “this” as the fact of suffering itself. Others read it as the whole picture Paul just praised (their endurance plus the pressures). Either way, Paul is pointing to what can be seen in their experience as evidence for his claim about God’s fair judgment.
What “counted worthy” means. Some take it mainly as God recognizing them as fitting for the kingdom at the end (a verdict and vindication). Others think it also implies God making them fit through suffering, so that hardship is part of how they become “worthy.” The text clearly says the goal is being “counted worthy,” but it does not spell out the exact mechanism.
When “relief” begins. Some read v.7 as relief that begins only at Jesus’ revealing. Others allow that present encouragement may be real now, while the full reversal is future. Verse 7 anchors the decisive relief to the revealing of Jesus.
Why the disagreement exists
Paul’s wording is compact and can be read in more than one direction: “this” has a near context but not a single explicit noun; “counted worthy” can describe either recognition or a process leading to fitness; and the time phrase in v.7 (“when…revealed”) can be taken as the start of relief or the climactic moment of relief.
What this passage clearly contributes
This passage frames suffering for God’s kingdom as compatible with God’s fairness, not evidence against it. It also contributes a strong claim about future moral reversal: God will respond to oppression with repayment, and will respond to the oppressed with rest, timed with Jesus’ revealed arrival from heaven. The justice described is both moral (“it is a righteous thing,” v.6) and public (Jesus “revealed,” v.7; compare Acts 17:7 for the political tension around another “king”).