Paul says believers do not need to be told about the times and seasons, for they know the day of the Lord comes like a thief in the night. For those who are unprepared, it will come suddenly. But believers are not in darkness. You are all children of light and children of the day. So they should not be sleepy or careless like others but should watch and be sober.
Because they live in God's light, they should put on the breastplate of faith and love, and the helmet of the hope of salvation. For God didn't appoint us to wrath, but to the obtaining of salvation through our Lord Jesus Christ. Jesus died for them so that they would live together with Him. Therefore they should encourage one another and build each other up, as they already do.
Paul closes with a series of brief commands. Honor those who labor among them in the Lord, and be at peace. Warn the disorderly, encourage the faint-hearted, support the weak, and be patient toward all. See that no one returns evil for evil. Always rejoice. Pray without ceasing. In everything give thanks, for this is the will of God in Christ Jesus toward you. Don't quench the Spirit. Test all things, and hold firmly that which is good. Paul prays that the God of peace will sanctify them completely, and he adds a promise: He who calls you is faithful, who will also do it.