Travail (μοχθον). Old word for difficult labour, harder than κοπος (toil). In the N.T. only here, 2 Thessalonians 3:8; 2 Corinthians 11:27. Note accusative case here though genitive with μνημονευω in 1 Thessalonians 1:3.

Night and day (νυκτος κα ημερας). Genitive case, both by day and by night, perhaps beginning before dawn and working after dark. So in 1 Thessalonians 3:10.

That we might not burden any of you (προς το μη επιβαρησα τινα υμων). Use of προς with the articular infinitive to express purpose (only four times by Paul). The verb επιβαρεω is late, but in the papyri and inscriptions for laying a burden (βαρος) on (επι-) one. In N.T. only here and 2 Thessalonians 3:8; 2 Corinthians 2:5. Paul boasted of his financial independence where he was misunderstood as in Thessalonica and Corinth (1 Thessalonians 2:2), though he vindicated his right to remuneration.

We preached (εκηρυξαμεν).

We heralded (from κηρυξ, herald) to you, common verb for preach.