What does Luke 20:11 mean?

Jesus is using the parable of the wicked tenants to warn a group of Jerusalem businessmen and high priests. If they do not accept the authority of God's messengers, they're going to lose everything (Luke 20:9–18).

In the parable, a landowner sends a servant to collect some of the grapes from tenants who take care of his vineyard. When the first servant arrives, the tenants beat him; they do the same for the second. "Shamefully" means disrespectfully, which was a great offense in an honor/shame culture such as the ancient Middle East. By shaming the servant, they show public disrespect for the servant's master.

The parable is an allegory: a simplified symbolic representation of other events or persons. In this case, the landowner is God. The tenants are the Jewish leaders (Luke 20:19). The servants are God's prophets. Being God's prophet in the days of the Old Testament was dangerous (1 Kings 18:4; Acts 7:51–53).

The job of the prophets was mainly to remind the kings what God wanted them to do: to rule the people justly, encourage God-worship, destroy pagan idols, and rely on God for the nation's protection. Some kings did this well, but most didn't. The kings' sins were a major factor in the dissolution of the northern kingdom of Israel and the Babylonian captivity of the southern kingdom of Judah. It is why the Romans ruled over Israel during Jesus' earthly ministry.

The Jews had such a long history of abusing God's prophets that Jesus spends three verses repeating the fates of these poor servants. Matthew 21:35–36 explains that sometimes the servants went in groups, and some of them were killed.