For neither were we at any time found using words of flattery, as you know, nor a cloak of covetousness (God is witness),
God is witness; which is properly an oath, a solemn appeal to God; for since covetousness is an internal and secret sin, and may be so coloured and disguised as not easily to be discerned, as flattering words may, the apostle therefore calls God to witness the truth of what he had said.