burden
This translation renders the Greek term βάρος ( baros) here as “burden,” thus translating “been a burden” instead of something like “assert our authority” or “made demands.” To render this word as “burden” helps readers see the same root βαρ (barepibareō) in verse 9, which is likewise translated “burden” to show this intentional consistency by Paul (see also 2 Thess 3:8). Additionally, “burden” helps readers see more clearly the loving and tender tone Paul has in writing to the Thessalonians, as well as his heart when ministering in their midst, which is highlighted in the following verse with his analogy.

gentle
There is a text-critical issue in this verse regarding whether the original Greek word here is ἤπιοι (ēpioi; “gentle”) or νήπιοι (nēpioi; “infants”). This translation usually follows the NA27, which has νήπιοι (nēpioi; “infants”). But considering textual and contextual evidence in this specific case, the better choice seems to be ἤπιοι (ēpioi; “gentle”). Although there is some strong manuscript support for νήπιοι (nēpioi; “infants”), the internal evidence more likely points to “gentle,” as the “infant” reading seems to create a contradictory metaphor: “we were infants among you, like a nursing mother tenderly cares for her own children.” Furthermore, the previous word (ἐγενήθημεν; egenēthēmen) ending in -ν (-n) may point to an error called haplography in duplicating it at the beginning of ἤπιοι (ēpioi). Thus, Paul is recounting the motherly gentleness with which he and his ministry companions cared for the Thessalonians.

pleased
The translation here is “pleased” rather than “well-pleased” in order to preserve consistency in rendering the Greek verb εὐδοκέω (eudokeō) in various contexts. In contexts where it refers to God, it is usually rendered as “well-pleased,” and in contexts where it refers to people, as here, it is often simply rendered something like “pleased.” Paul expresses his pleasure to minister to this church sacrificially out of his deep love for them. Only genuine love for others, derived from a true understanding of the gospel, manifests itself in one’s affections to find pleasure in ministering in such a way as to be willing to selflessly sacrifice.

without ceasing
The word ἀδιαλείπτως (adialeiptōs) here carries the meaning of “incessantly,” “unceasingly,” or “constantly.” It is consistently translated as “without ceasing” in Paul’s letters to the Thessalonians (as well as its only other occurrence in Rom 1:9). This helps the reader to recognize it anywhere it appears. Here, Paul explains how he never ceases to thank God that the Thessalonians saw the word of God according to its true nature and source.

at work
The translation “at work” rather than “performs its work” gives a simpler rendering of the Greek verb ἐνεργέω (energeō) here. The English word “energy” can be seen in this word, as it carries the meaning of something being at work, in effect, or in operation. Paul pictures the word of God actively working in believers, being manifest in belief, obedience, and sanctification. The translation “at work” pictures this well.

and do not please God, and are hostile
Paul uses a chain of participles here to describe the Jews in verse 14—they “killed” (ἀποκτεινάντων; apokteinantōn), “drove out” (ἐκδιωξάντων; ekdiōxantōn), and do not “please God” (ἀρεσκόντων; areskontōn)—who also are hostile to all men. To render the καί (kai) here as “and” instead of “but” helps show that these Jews have four characteristics that describe how and why they are a hinderance to the gospel (v. 16). Thus, their hostility to all men is not a contrast with what came prior (which “but” might suggest), but a continuation of the description.

boasting
“Boasting” provides a consistent and literal translation of the Greek word καύχησις (kauchēsis). While Christians are never to boast in themselves, they are right to boast in the Lord. Here, Paul calls the Thessalonian believers a “crown of boasting,” not because he can boast in the Thessalonians themselves, but because God is clearly the one working in them through His word (cf. v. 13). Paul emphasizes that they are a crown of boasting to him and his ministry companions to reaffirm his love for them, even though he had not been able to visit them in person (cf. v. 18).