That is why indicates a very general connection between the previous verses and the aim of Paul’s prayer, which he is about to state in a little more detail. The Greek contains an additional word, “also,” which does not here imply any kind of contrast, but indicates that Paul is about to make another statement about what he and his colleagues do. Most translations omit it.
In a number of languages it may be necessary to specify what that refers to in the phrase that is why. The content of the following two verses would seem to point clearly to the special glory which the believers are to render to the Lord on that special Day. Certainly that is not a reference to possible punishment. In some instances one may be able to use a very general connective such as “therefore,” but where something more specify is required, it may be necessary to say “because of the honor which you are going to give to the Lord, we always pray for you.”
We ask our God to make you worthy is literally “that our God may make you worthy.” Good News Translation begins a new sentence by repeating in other words the end of the previous sentence. Paul probably means, not “we pray in order that God may make you worthy”, but “the subject of our prayer is that God will make you worthy.” In a number of languages it is necessary to introduce direct discourse with any expression of asking favors of God or praying to God. For example, it may be necessary to say “We pray to our God, Make the believers in Thessalonica worthy of the life you called them to live.”
Make you worthy usually means “consider you worthy,” but Good News Translation‘s translation is justified by the context; the rest of the verse clearly shows that a new kind of conduct is involved. (A similar difficulty was noted in 2 Thess. 1.5). It is difficult in some languages to find an expression which fully translates the term worthy. In some instances the equivalent may be “make you the kind of people who deserve the life.” It may even be necessary to use an expression equivalent to “make you good enough to live the life.” This is not directly a petition for sanctification; it is a request that the lives of the Thessalonians will come up to the standard expected of those who have been called of God to live in a very special way.
The life he has called you to live is literally “the calling,” but this means, not only the act by which God first called the Thessalonians, but the life which he intended they should follow. There are problems involved in the expression the life he has called you to live. It is impossible in some languages to speak of “living a life.” However, one can say “worthy of the way in which he has called you to live.” But then, there are often difficulties involved in the word called. This must not be rendered in such a way as to suggest “calling to” or “shouting at.” The closest equivalent in some languages is an expression relating to the process of inviting or even summoning.
All your desire for goodness is the most probable way of understanding the next words (cf. Barclay “that [God] may turn all your good intentions into actions”). Paul is speaking of an activity of God which, he prays, will bring to good effect the Thessalonians’ own desire for good. The La Sainte Bible: Nouvelle version Segond révisée text understands Paul to mean that the good desires are also God’s, and translates “that [God] may accomplish in you … all the benevolent designs of his goodness.” This translation is less probable (cf. the footnote to the La Sainte Bible: Nouvelle version Segond révisée text). Traduction œcuménique de la Bible leaves the matter open, producing the vague translation: “that [God] may grant you to accomplish all the good desired.”
The request implied in may he, by his power, fulfill all your desire must be introduced in some languages by an expression of prayer or requesting, for example, “we pray to God that he will fulfill.”
Fulfill all your desire for goodness may be expressed in some languages as “make it possible for you to do all the good which you want to do,” or “… to be good to others in all the ways that you desire to do so.”
In the Greek of by his power, the possessive his is understood. Some versions translate by his power as “powerfully.” By his power comes at the end of the verse in the original, so it is not quite certain whether this phrase refers only to complete your work of faith or to fulfill all your desire for goodness also. The two phrases introduced by complete and fulfill (one word in Greek) are so similar in meaning and so closely linked that it is best to take by his power as referring to them both. Barclay chooses “that he may turn all your good intentions into actions, and powerfully help you to live the life that faith demands.” In some languages it is extremely difficult to speak of power as a means by which something is accomplished. Since power is essentially a quality of God himself, and not an instrument, it must be expressed in some languages as cause, for example, “because he is so powerful,” or “because he has the power to do so.”
The last part of Barclay‘s translation (“the life that faith demands”) corresponds to Good News Translation‘s more literal your work of faith. Your is only implied in the Greek, but many translations add it, and rightly so. Complete your work of faith may mean either (1) “make perfect the activity of your faith” (Bible en français courant), or (2) “complete the things you do because you believe” (cf. Jerusalem Bible “complete all that you have been doing through faith”). The difference in meaning is slight, since a purely inward activity of faith would be difficult to imagine, and it is certainly not intended in 1 Thess. 1.3, where a very similar phrase is used. The second alternative would produce a clearer translation.
Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on Paul’s Second Letter to the Thessalonians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .