Acts 23:3

‘Then said Paul to him, “God will smite you, you whited wall. And do you sit to judge me according to the law, and command me to be smitten contrary to the law?” '

But Paul knew his Law. And he knew that the Law did not allow such treatment to one who was on trial (e.g. Leviticus 19:15). So he retaliated verbally with a returning insult (and afterwards admitted that he should not have done so, however justified it might have seemed). He warned the High Priest that he would be answerable to God for his action. A ‘whited wall' is one that has been painted to hide its imperfections so that it can pretend to be what it is not (compare Ezekiel 13:10; Ezekiel 13:14; Matthew 23:27) and was liable to be exposed by judgment (Ezekiel 13:10; Ezekiel 13:14). He was saying that the judge was a hypocrite and would himself face judgment for it. Like Peter, Paul could be a bit precipitate (compare Galatians 3:1; Galatians 5:12; Philippians 3:2 and contrast 1 Corinthians 4:12 - Barnabas would never have done it. But then he would never have achieved what Paul did).

He was quite rightly pointing out that the judge also came under the eye of the divine judge. But he should have remembered that he was speaking not only to the High Priest but to the whole court, although in fact his words were an unconscious prophecy (or an effective curse) for Ananias was murdered by terrorists at the beginning of the Jewish war.