What does Luke 21:12 mean?
Prior to this passage, the disciples were probably feeling incredibly good about themselves. They witnessed as Jesus proved He had the authority of the Messiah, and the religious leaders were unqualified (Luke 20). They followed Jesus to the Mount of Olives, east of Jerusalem and above the temple Mount. As they looked at the temple, they took pride in the beauty of the buildings where they can worship God (Luke 21:5).Jesus had to tell them that their joy will be short-lived. A time will soon come when the temple will be destroyed so thoroughly not one stone will be stacked on another (Luke 21:6). History confirms that this happened: when the Romans sacked Jerusalem in AD 70.
The warning about the disciples' persecution echoes the one about the temple. For the moment, the disciples are popular and the temple is beautiful. Soon, the Jewish religious leaders Jesus debated will arrest, beat, and kill the disciples. Shortly after, the Roman army will burn the temple.
The two ideas are closely related: the Holy Spirit will leave the temple and enter the disciples (Acts 2:1–4). When the temple is destroyed, God-worship as given in the Mosaic law becomes impossible, because there is no altar. When the disciples are arrested and beaten (Acts 4:1–22; 5:17–42; 7:54–60; 8:1–3; 12:1–4), however, the Holy Spirit will take over. He will empower the disciples to preach in His name before kings and governors (Acts 13:4–12; 24:1–21; 25:13—26:29). And even if their families orchestrate their deaths, God will secure their eternal lives (Luke 21:13–19).
Being brought before the synagogues is more serious than it appears. Jewish evangelists typically start teaching about Jesus in the synagogue because the Jews there have the context of the Old Testament prophecies about their Messiah. That's what Stephen did; he was killed for it (Acts 6:8–15; 7:54–60). Jewish Christians didn't suddenly become Gentiles; they still followed the Mosaic law. To be kicked out of the synagogue in Gentile territory means to have no access to their home culture or the food they need to stay clean. The context of the book of Galatians is that Jewish Christians told Gentile Christians they had to become circumcised to be saved. They knew it wasn't true, but they couldn't associate with unclean Gentiles and still attend the synagogue. Getting them circumcised was the only way they could live in both worlds.