Adam Clarke on 1 Thessalonians 2:9

Ye remember - our labor and travail - From this it appears that St. Paul spent much more time at Thessalonica than is generally supposed; for the expressions in this verse denote a long continuance of a constantly exercised ministry, interrupted only by manual labor for their own support; labouring night and day, because we would not be chargeable to you. Probably Paul and his companions worked with their hands by day, and spent a considerable part of the night, or evenings, in preaching Christ to the people.