Source
First Epistle to the Thessalonians
Paul's letter to the young church at Thessalonica in Macedonia. It is generally considered the earliest of his surviving letters and possibly the oldest book of the New Testament.
References
Quotes (1)
“In every thing give thanks: for this is the will of God in Christ Jesus concerning you.”
— Paul the Apostle, 1 Thessalonians 5:18 (KJV)