What does Luke 23:18 mean?
Pilate has questioned Jesus and found Him innocent. Then he sent Jesus to Herod Antipas, who agreed. Finally, he has given the results of his investigation to Jesus' accusers: the chief priests, elders, and scribes, as well as the mob they've enticed to their side. They won't be satisfied if Jesus is simply released. Pilate knows this, so he's promised to beat Him first (Luke 23:1–16).Other Gospels note that releasing a prisoner was a Passover custom for Pilate in Judea (Matthew 27:15; Mark 15:6). It's unclear how the fortunate prisoner is chosen, but Pilate wants it to be Jesus. He seems to give the people the option: Jesus, who has done nothing worthy of death, or Barabbas, a murderer and insurrectionist (Luke 23:19). Luke simply notes that the mob demands Barabbas; Matthew 27:17 clarifies that Pilate makes them choose. His hope was probably that the people wouldn't side with an actual insurgent over someone like Jesus. He is wrong.
"They all" includes the crowd brought by Jerusalem's religious leaders. Some teachers claim, strangely, that this mob are the exact same people who accompanied Jesus into Jerusalem during the triumphal entry (Luke 19:29–40). It's possible that some who celebrated Jesus' initial arrival turned against Him. But it's more than a stretch to presume that all or nearly all those condemning Him now were His supporters only a few days ago.
This event happens during Passover in Jerusalem. There are tens of thousands—if not hundreds of thousands—of Jews who have come from all over the Roman Empire. The crowd at the triumphal entry likely came from the Jordan River, like Jesus, so they were from Galilee, Decapolis, and Perea. Jesus spent much of His ministry in Galilee and Decapolis; there's little reason the people who benefited from His healing miracles would demand His death, now.
It's more likely these Jews are from outside of the local area. When Stephen preached and performed miracles in Jerusalem, it wasn't the locals who condemned him, it was people from northern Africa and modern-day Turkey (Acts 6:8–15). And when Paul came to Jerusalem, it wasn't the Jews from Judea who attacked him but the Jews from the district in southwest Asia Minor (Acts 21:27–28). Devout Jews from outside of Judea and Galilee, who come to Jerusalem rarely and know little about Jesus, would be easier to influence than those who knew of Jesus and witnessed His miracles (Matthew 27:20; Mark 15:11).
Luke's narrative highlights the fact that the nation of Israel, overall, was complicit in Jesus' death. This doesn't make them solely responsible for it, nor their descendants liable. Instead, it reinforces the idea that all people sin and reject God and need redemption (Romans 3:10).