God examines our hearts.
Don’t seek glory from men (implied).
Abstain from sexual immorality; love (and comfort) one another; lead a quiet life, attend to your own business, and work with your hands, so that outsiders will respect you and you won’t be in need.
The dead shall rise when the Lord returns. (I Thessalonians 4:17 is the famous “rapture” verse.)
Be alert and self-controlled; encourage and build up one another.
Live in peace with each other, and admonish the unruly, encourage the fainthearted, help the weak, and be patient with all. Be forgiving, not vengeful; “be kind to each other and everyone else” (note those last three words). Always be joyful, “pray without ceasing” (5:17), and give thanks in all circumstances. Christ is coming.
Also (5:21): “Test everything.” And somewhat more cryptically (5:19-20): “Do not quench the Spirit; do not despise prophetic utterances.”
Note that Paul’s faith-hope-love triptych, most famous in I Corinthians 13:13. is also present in I Thessalonians 1:3 and 5:8.
We should thank God for the good things, and pray for good things.
Persevere through persecution. God (indeed, Jesus) will punish (eternally) those who persecute Christians.
The “man of lawlessness” (Antichrist) will come before the Second Coming.
Stay away from the wicked/unruly. If you don’t work, you don’t eat (in particular, don’t stop working in anticipation of the Second Coming). As you wait, keep working quietly and doing good, and admonish your fellow Christians who don’t.
The basic point is that, while we await the Second Coming, we have to live and work responsibly in this world. And, as Paul says in I Thessalonians 5:2, you won’t know when He’ll come: “[T[he day of the Lord will come just like a thief in the night.”