After the aside of verse 7, Paul now returns to his main theme. Verse 8a repeats part of 6b, with an emphatic transitional but we to mark the contrast between Christians and the others. The Greek (literally “but we, being of the day, let us be self-controlled”) implies a relation of reason and result: “since we belong to the day, let us exercise self-control.”

For the expression we belong to the day, see the discussion under 1 Thess. 5.5; for we should be … sober, see 1 Thess. 5.6. There should, of course, be a close correspondence between the expressions used in verse 8 and the same expressions used in previous verses, since verse 8a summarizes the complex figures of speech which begin with verse 4.

Since the beginning of this chapter, Paul has been writing sentences which, for him, are comparatively short. In the UBS Greek text, verses 1-6 consist of four sentences of between 16 and 26 words each, while verses 7-10 form a single sentence of 55 words. Verse 11, like 4.18, which it resembles in other ways, is a short, empatic, concluding sentence. The emotive tone has been correspondingly lower, partly because he has been mentioning those who stand outside the personal relationship which links him with his readers. Now he begins to write once more about the faith which they have in common, and the emotive tone rises in verse 9-10 to a climax of the whole section (4.13–5.11). The process begins in verse 8, although the sentence has formally begun with verse 7, which we have identified as an aside from the point of view of its meaning.

Paul several times compares the Christian’s spiritual resources with arms and armor (Ephesians 6.13-17; Romans 13.12; 2 Corinthians 6.7; 10.4; cf. Isaiah 11.5; 59.17; Wisdom 4.17-20). He makes no attempt to be consistent in comparing the various Christian virtues with the various pieces of military equipment. Here faith, love, and hope are mentioned in the same order as in 1.3 (see the notes on that verse). Typically, Paul now urges his readers to exercise qualities which, at the beginning of his letter, he has praised them for already possessing (cf. also 3.12; 4.1).

Hope of salvation: salvation is the object of hope (cf. Die Bibel im heutigen Deutsch “hope for salvation”). This phrase is the pivot on which the following verse turns and to which it is related in an unfolding sequence.

These figures of speech, which liken certain Christian virtues to armor, are extremely difficult to translate meaningfully into some languages. There are several reasons for this. In the first place, armor is quite unknown in some cultures, and therefore there are no terms for pieces of armor nor can people readily imagine how armor was used. In the second place, it is extremely difficult to liken events or states implied in “trusting” and “loving” to something as concrete as a breastplate. In the third place, faith and love must often be expressed by verbs, and this makes the comparison far more difficult. An equivalent of 8b in some languages would be “you must trust and love God: then you will be wearing, as it were, a protection for your body.” It simply does not make sense in some languages to talk about “wearing faith and love.” Furthermore, it is the function of the breastplate which must be made clear; otherwise any meaningful connection between “faith” and “love” on the one hand, and the “breastplate” on the other, will be lost.

Our hope of salvation may be rendered in some languages as “we should look forward confidently to our being saved,” or “… to God’s saving us.” Then the phrase as a helmet may be translated as “this will be like a protection for our heads.” The need for the breastplate and the helmet is, of course, because of the spiritual conflict with Satan, but this aspect is not specifically brought out in this passage as it is in Ephesians 6.16-17.

Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on Paul’s First Letter to the Thessalonians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .