Paul wrote this letter to strengthen and encourage the church in Thessalonica. Paul reminds them of the second coming of Jesus Christ. Throughout this letter, Paul focused on the principles of Faith, Hope, and Love.
In chapters 1-3: Paul writes to the Thessalonians about the WORD and POWER of the Gospel. How without Authority, you cannot be properly taught the Gospel. He explains that he did not just come to them in WORD, “…but also in POWER, and in the Holy Ghost…” (1 Thessalonians 1:5) Paul then goes onto explain how the converts of the church bring him so much joy; and how himself and others who preach the Gospel do it for the purpose of bringing others to Christ.
In chapters 4-6: Paul highlights Love and Hope. He urges the members of the Church (the Saints) to love on another and prepare themselves for the Second Coming of Christ. He explains that we should hold fast to what is good and “Rejoice evermore.” (1 Thessalonians 5:16)