John 8:46,47 - Coke's Commentary on the Holy Bible

Which of you convinceth me of sin?— Can convict me of sin? Heylin. The only reason for refusing assent to a person is, either because he is not deserving of credit, or because what he asserts is improbable. Our Lord shews that they could not object to him for either of these reasons, particularly the first; they could not convince him of sin; they could not shew that his conduct and life were reproachable; they could notprove that his doctrine was false; they could not say, that he reproved them unjustly for their actions; and as therefore they could not but acknowledge that his doctrine and life were such as became a divine messenger from God, he might well ask them what was the reason why they did not believe on him?—a question, indeed, to which he gives a full reply in John 8:47. See also John 8:41.