Expositor's Bible Commentary Commentary 1 Thessalonians 2:10

"Ye are witnesses, and God [also], how holily and righteously and unblameably we behaved ourselves toward you that believe:" — 1 Thessalonians 2:10 (ASV)

Paul appeals to the Thessalonians as witnesses of how both the missionaries’ religious piety and moral conduct among them could not be faulted. God also is called to attest to whatever was hidden to human eyes. All this was for the sake of the believers.