1 Thessalonians 2:10
Ye [are] witnesses, and God [also], how holily and justly and unblameably we behaved ourselves among you that believe:
Note 13 at 1Th 2:10: The Thessalonians had to admit that Paul's conduct was holy, righteous, and blameless while he was with them. They knew that what he was saying was true. Paul also invoked the Lord as a witness (1Th 2:5 and this verse). Paul's conscience was clear. He had behaved himself in a godly manner the whole time he was with them. How many of us would be willing to call on the Lord to bear witness to our actions and motives?