Paul had previously commended the Thessalonians for allowing God's Word to work in their lives (1 Thessalonians 2:13).  That was particularly demonstrated when they were under persecution.  God's Word sustained them when they were pursued and harassed by religious people who hated Jesus.  Opposition did not stop them from believing, instead it affirmed their faith; as it did for the churches in Judea.
 
Although the Jews should have welcomed their Messiah, they resisted Him and were determined to kill Him.  Paradoxically, Paul was also one of them before he met the risen Jesus (Galatians 1:13).  Paul was present at Stephen's martyrdom (Acts 22:20) and could personally remember how much he loathed people who believed in Jesus (Acts 26:10-11).  But in the same way that the death of the Lord Jesus enabled salvation for many, the persecution of the believers had the effect of forcing many to leave Jerusalem and the surrounding area.  As they travelled, they spread the gospel and churches were formed (Acts 8:1-4).
 
Although God uses the anger of man to achieve His purposes (Psalm 76:10), He does not excuse their evil behaviour.  Paul calls it 'heaping up sins to the limit'.  It was like the wicked Amorites who lived in Caanan: God brought punishment on them when their record of sin proved their arrogant rebellion (Genesis 15:16).  Unrepentant sinners face judgement, however religious they may have been. But God is particularly offended when persecutors inhibit believers proclaiming the gospel and hinder the unsaved reaching out to the Saviour.
 
Suffering should be expected by people who follow the crucified Christ (Philippians 1:29).  So when it comes, we should not be surprised (1 Peter 4:12-14).  Some Christians think that opposition and suffering are signs that God has removed His blessing because of their sins, or because they have not been zealous enough: that comes from false teaching. Opposition is normal for faithful disciples of Jesus (2 Timothy 3:12); it does not mean that God has left you, because His Word sustains the faithful (Isaiah 50:4).  Be encouraged when the Lord entrusts you to bear hostility (Matthew 5:10-12).  He is refining you (1 Peter 1:7).  God's blessing is not only in abundantly supplying what you need, but also experienced in generously sustaining you through great hardship.  Either way, thank Him and trust Him for whatever may come tomorrow.