What does Acts 23:3 mean?
The Sanhedrin is interrogating Paul, because the Roman tribune wants to know why he was attacked in the temple. The Roman official hopes the Jewish religious leaders can lend some insight. It isn't going well. Paul's not interested in the mob attack. He's focused on bringing the members of the Sanhedrin to accept Jesus as their Messiah. He starts by insisting on his innocence. The Sanhedrin considers him a heretic, however, and the high priest has him struck (Acts 23:1–2).Paul is startled, insulted, and indignant. This is not a criminal trial and he has not been convicted; they have no right to punish him. Deuteronomy 25:1–3 says a person may be beaten only if they are convicted of a crime. The comparison to a "whitewashed wall" is probably related to Jesus' description of the Pharisees to whitewashed tombs (Matthew 23:27). Both metaphors refer to someone who looks respectable on the outside but is corrupt and rotten on the inside.
Apparently, Paul doesn't know that the authority behind the blow is the high priest Ananias. Some scholars posit it has been so long since Paul was in Jerusalem he didn't know which of the men before him is the high priest. Others think the "thorn" in his flesh (2 Corinthians 12:7) is continued eyesight problems from when he first saw Jesus (Acts 9:3–9). When he is told, he semi-apologizes, inferring he didn't know because Ananias wasn't acting like a high priest (Acts 23:5).