Jamieson, Fausset and Brown on 1 Thessalonians 5:23

23. the very God--rather as the Greek, "the God of peace Himself"; who can do for you by His own power what I cannot do by all my monitions, nor you by all your efforts (Ro 16:20; He 13:20), namely, keep you from all evil, and give you all that is good.

sanctify you--for holiness is the necessary condition of "peace" (Php 4:6-9).

wholly--Greek, "(so that you should be) perfect in every respect" [Tittmann].

and--that is, "and so (omit 'I pray God'; not in the Greek) may your ... spirit and soul and body be preserved," &c.

whole--A different Greek word from "wholly." Translate, "entire"; with none of the integral parts wanting [Tittmann]. It refers to man in his normal integrity, as originally designed; an ideal which shall be attained by the glorified believer. All three, spirit, soul, and body, each in its due place, constitute man "entire." The "spirit" links man with the higher intelligences of heaven, and is that highest part of man which is receptive of the quickening Holy Spirit (1Co 15:47). In the unspiritual, the spirit is so sunk under the lower animal soul (which it ought to keep under) that such are termed "animal" (English Version. "sensual," having merely the body of organized matter, and the soul the immaterial animating essence), having not the Spirit (compare 1Co 2:14; see on 1Co 15:44; 1Cor 15:46-48; Joh 3:6). The unbeliever shall rise with an animal (soul-animated) body, but not like the believer with a spiritual (spirit-endued) body like Christ's (Ro 8:11).

blameless unto--rather as Greek, "blamelessly (so as to be in a blameless state) at the coming of Christ." In Hebrew, "peace" and "wholly" (perfect in every respect) are kindred terms; so that the prayer shows what the title "God of peace" implies. Bengel takes "wholly" as collectively, all the Thessalonians without exception, so that no one should fail. And "whole (entire)," individually, each one of them entire, with "spirit, soul, and body." The mention of the preservation of the body accords with the subject (1Th 4:16). Trench better regards "wholly" as meaning, "having perfectly attained the moral end," namely, to be a full-grown man in Christ. "Whole," complete, with no grace which ought to be wanting in a Christian.