Ye are witnesses, and God also, how holily and justly and unblameably we behaved ourselves among you that believe:
Ye are witnesses - as to our outward conduct.
God - as to our inner motives.
Holily - toward God.
Justly - toward men.
Unblameably - as to ourselves.
Behaved ourselves, х egeneetheemen (G1096)] - 'were made to be;' namely, by God.
Among you that believe - Alford, 'before (i:e., in the eyes of) you that believe:' whatever we seemed to the unbelieving. As 1 Thessalonians 2:9 refers to their outward occupation, so 1 Thessalonians 2:10 to their character among believers. Ellicott, 'to you that believe:' for your interest. Their being believers would enable them to appreciate his 'behaviour' in respect to them.