"Do not put out the Spirit's fire;" NIV translation
We may ask ourselves how we could put out the fire and it is actually an easy but slow process. In our personal lives, this is simply ignoring the prompting of the Holy Spirit in your everyday walk. This builds to become a habit so that your heart can actually get so hardened that you no longer even hear God speaking to you through the Spirit.
"do not treat prophecies with contempt." NIV translation
There are those who show contempt for the prophecies in the Bible. An example is the fact that most people do not live as if they believe that Jesus could come back today.
"Test everything. Hold on to the good. Avoid every kind of evil." NIV translation
Hold onto the things of God and get rid of the things of the devil. But, how do we test things? We find the answer to that in 1 John 4.
"May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ. The one who calls you is faithful and he will do it." NIV translation
Paul prays for the readers to be pure and holy. He reminds us that it is not through us that this happens but through the Holy Spirit. That is what Peter was talking about in 1 Peter 1:2 when he said it was the work of the Spirit.
"Brothers, pray for us. Greet all the brothers with a holy kiss. I charge you before the Lord to have this read to all the brothers." NIV translation
Paul closes with three simple requests and the first is prayer. Paul was a man of prayer and so he desired to have others pray for him just as he prayed for them. He reminds them to greet their fellow Christians warmly and to read this letter to all of the believers. This is a letter of instruction to help them to grow in their walk with Christ and so he wanted all of them to hear it.
"The grace of our Lord Jesus Christ be with you." NIV translation
Paul ends this first letter to the Thessalonians with a prayer for grace for the believers. We all need grace on a daily basis and Paul knew that he needed it too.