John Calvin on 1 Thessalonians 2:10

10 Ye are witnesses. He again calls God and them to witness, with the view of affirming his integrity, and cites, on the one hand, God as a witness of his conscience, and them, “Les Thessaloniciens;” — “The Thessalonians.” on the other hand, as witnesses of what they had known by experience. How holily, says he, and justly, that is, with how sincere a fear of God, and with what fidelity and blamelessness towards men; and thirdly, unreproachably, by which he means that he had given no occasion of complaint or obloquy. For the servants of Christ cannot avoid calumnies, and unfavorable reports; for being hated by the world, they must of necessity be evil-spoken of among the wicked. Hence he restricts this to believers, who judge uprightly and sincerely, and do not revile malignantly and groundlessly.