Theological Center of 1 Thessalonians

At the center of the theological thought of 1 Thessalonians stands the belief that God elects (1:4) and then calls (2:12; 5:24) believers through the message of the gospel (1:5; 2:13), and that he appoints them to future salvation through Jesus Christ, who died for them so that they might live with him at his victorious coming from heaven (5:9–10). 

—Charles Wanamaker, "1 Thessalonians, Book of," DTIB, 795.