In these verses Paul uses the words "we," "our," "ourselves," and "us" to refer to himself and Timothy and possibly others who served with them. These words do not include the people he was writing to. (See: [[rc://en/ta/man/translate/figs-exclusive]])
Paul speaks of not being guilty as if his conscience were a person that could speak. AT: "We know by our conscience" (See: [[rc://en/ta/man/translate/figs-personification]])