I. There is much of instruction and comfort in this Apostolic prayer. The blessing prayed for is that the Thessalonian converts may be sanctified wholly, that their spirit and soul and body may be preserved. The Apostle adopts the trichotomy which in some form or other may be said to belong to almost all systems of philosophy "body, soul, spirit" It is the combination of these three which makes up our nature; it is the due relations between these three which constitute our sole possible happiness; it is the right training of these three that is the object of that lifelong education which should begin in our earliest years, and end only with the grave. In the case of Christ's people, the Apostle's prayer is that body, soul, and spirit be preserved entire, without blame, being sanctified wholly each in its complete measure and perfect proportions. Delivered from the dominion of sin and Satan, they are in God's keeping unto holiness. The whole man is to become wholly man and God.
II. St. Paul next turns aside, very characteristically, to ask the pleadings of his Thessalonian friends with the God of peace on behalf of himself and his fellow-labourers. He who was giving thanks always for them all, making mention of them in hisprayers, in the yearning love of his heart now asks them to make mention of himself in theirprayers. Such is Christian fellowship. The Apostolic teacher turns from instruction and exhortation and warning to supplication for help not man's help, indeed, but God's yet God's help brought near to him through the intercessory prayer of God's own people.
III. "The grace of our Lord Jesus Christ be with you all." In all the variations with which it appears in the Pauline epistles, this benediction never has the word "grace" a-wanting. Thus, his first epistle begins and closes with that word, which, above all others, reveals the summed sweetness of the whole Gospel. Those who have the grace of our Lord Jesus Christ with them on earth, cannot fail to have glory with Him hereafter in heaven.
J. Hutchison, Lectures on Thessalonians,p. 238.