Gordon Fee in his book “Pauline Christology” commenting on 1 & 2 Thessalonians makes the interesting observation that Paul does not deliberately seek to explain the hypostatic union of Christ.

The Christology that presents itself in these letters is especially note-worthy, first of all because there is not a self-consciously christological moment in either of them.  That is, there is no passage where Paul is deliberately trying either to set forth Christ as divine (or human, for that matter) or to explain the nature of his divinity. His interest in Christ, as we come to expect in his later letters, is primarily soteriological.  “Our Lord Jesus Christ” is the divinely given Savior, who “died for us”7 (1 Thess 5:9–10) and whose resurrection has assured us that “we will live with him” (5:10) because he has also secured our “rescue from the coming wrath” (1:10) and our sharing in the coming glory (2 Thess 2:14). Thus “the Lord” is also the one whom believers “imitate” in their present suffering (1 Thess 1:6).8 In a similar manner, and as turns out to be the norm, Christ is therefore the basic content of the gospel (1 Thess 3:2; cf. 2 Thess 1:8), as well as the divine agent of much (the apostolic “instructions” [1 Thess 4:2]; the divine will [5:18]).  – Gordon Fee, Pauline Christology p.32-33