They give a further reason why they do not believe. We know where he is from.
It is the same with us before we know Christ. We hear things about the Christian faith, that are against the faith, and we take them up and believe them, and we do not enquire – What is the Christian faith? What did Christ do? What is it about? We do not want to know. We are superficial and these words apply to us. ‘Judge not according to the appearance’, according to sight, the Greek says. Really it means superficial judgement, just your superficial impression. ‘But judge righteous judgment.’ Find out and you will understand that he is truly the Messiah.