For Paul, he who calls you is always God the Father (cf. 2.12; 4.7). Here, as in 23b, Paul follows Jewish practice in referring to God without naming him directly. Good News Translation reverses the order of the sentence (cf. Revised Standard Version) for two reasons. First, there is a tendency in Greek for the greatest emphasis to occur at the end of the sentence, whereas in English the greatest emphasis tends to occur at the beginning. Second, Good News Bible is able, by reversing the order, to bring out more clearly the relation of result and reason expressed in because (implicit in the text). He who calls you will do it may require some shift in tenses, since the present calls might imply that God was at that very moment calling to the Thessalonians. This is a reference to what God constantly does, but for this to refer to the specific experience of the Thessalonians, it may be necessary to use a perfective tense, for example, “he who has called you will do it.” As in other contexts, call may suggest here a wrong meaning if it is translated literally. A translation should not suggest “shouting” but “inviting,” expressed in some languages as “God who has spoken to us to become his.”

He is faithful means “he is reliable,” “he keeps his promises.” The same God is at work from the moment at which the Thessalonians are called until the coming of Christ. This may be semantically restructured as “you can always trust him,” or “you may be sure he will always do what he has said.”

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 .