The Epistles of Paul the Apostle to the Thessalonians were written by Paul from Corinth about A.D. 52. These two letters are the earliest writings of the New Testament. Paul tells these Christians what sort of persons they must be, and that they must do their duty every day and not stand idle, waiting for the Second Coming.

2 Thessalonians 2

2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.