What does Matthew 23:33 mean?

The idea that Israel's most righteous people, the religious leaders known as the scribes and Pharisees, might be damned by God would have been mind-blowing to everyone in Israel. This would have been especially true for those religious leaders themselves. Yet Christ does not hesitate in His ongoing condemnation of them (Matthew 23:13–32). He even calls them harsh names: serpents and a brood of vipers. Snakes served as a symbol of evil throughout Israel's history (Matthew 3:7; 12:34).

The question asked here is rhetorical: Jesus is not "asking" so much as He is declaring that these men are doomed. This is not mere argument and debate. Jesus is the Judge and the King (John 5:26–27). The Pharisees do not realize it, but they stand condemned before God already, as they physically stand before the Messiah. Instead of bowing before Him in humility to request mercy, they are plotting to kill Him (John 11:53; Mark 3:6; Luke 22:2).

Jesus spoke often of hell and eternal judgment for those who rejected God's Savior and Son, the Messiah, even among God's chosen people (Matthew 22:13; 23:15).