For this reason
connects this verse with the preceding discussion. Paul thus brings to a conclusion his comments regarding Timothy’s mission and his own concern for the Thessalonians’ faith. It is noteworthy that many of the words and ideas of 1 Thessalonians 3:1–2 are repeated here, and this has the effect of marking 1 Thessalonians 3:1–5 as a literary unit in the letter.1 The close parallel between this verse and 1 Thessalonians 3:1 (So when we could stand it no longer …
), which connects with 1 Thessalonians 2:17–20, suggests that the conjunction διὰ τοῦτο (translated for this reason
) here in 1 Thessalonians 3:5 also looks back to Paul’s description of his enforced separation and frustrated attempts to return to Thessalonica.2
5 For this reason, when I could bear it no longer, I sent to learn about your faith, for fear that somehow the tempter had tempted you and our labor would be in vain.