2 Thessalonians was written shortly after 1 Thessalonians to the same church in Thessalonica. Paul has gotten word of something going on there which requires a follow-up letter. He is again writing of Jesus’ return and is probably clarifying something that had been misunderstood in his first letter. This chapter is acknowledging that they are serving God in an atmosphere of intense persecution. He reminds them that although they are suffering now, God will punish those who reject Jesus.
When we go through something in life that is difficult, we can wonder why we are suffering. If the suffering is the result of someone doing something to hurt us, we may wish God would protect us by punishing the other person. We live in the here and now and often want solutions in the here and now. Paul reminds us that God operates in eternity. There are many issues that won’t be resolved in this life. Faith means we can serve now and expect God to set everything right in his time.