What does Matthew 23:38 mean?

Mournfully, Jesus declared that He would have protected the people of Jerusalem, much as a hen would shield chicks under her wings (Matthew 23:37). Jerusalem, through her own people and their religious leaders (Matthew 23:1–3), rejected the protection of the Lord and has now rejected Jesus as the Messiah. That rejection will soon result in Jesus being unfairly condemned and executed (Matthew 26:1–5).

One consequence of this tragic rejection (John 5:39–40) is that God's protection will be entirely removed. Like a building abandoned and empty, there will be nothing left able to prevent disaster. These words echo those of the prophet Jeremiah (Jeremiah 12:7), speaking about Israel's prior experiences with judgment. They also point forward to the dire prediction Christ will make in the opening verses of the next chapter: "There will not be left here one stone upon another that will not be thrown down (Matthew 24:2)." This seems to be a reference to the huge temple in Jerusalem, perhaps a parallel meaning for the word "house" in this verse.

History records that within a few decades of Jesus' death and resurrection, tensions between Israel and Rome resulted in disaster. The Roman army was set loose on the city in AD 70, annihilating much of the population and literally tearing the temple apart brick-for-brick.