What does Luke 13:20 mean?

The kingdom of God is a significant theme in Jesus' "travelogue" (Luke 9:51—19:27). Throughout, the religious leaders work against God's kingdom (Luke 11:14–15, 29–32, 37–54; 13:10–17; 14:1–24). Because of people's hard-hearted rejection of Jesus, those who do follow Him will have to make serious sacrifices (Luke 12:22–53) and possibly face death (Luke 12:4–5).

The forces of the world and of demons, however, cannot stop God's kingdom. It is like a mustard seed sown in a garden that grows into a tree; it will grow slowly but once established it will not be removed. When it is big and sturdy enough, birds will roost in its branches. That is, people of the nations will find rest and protection (Luke 13:19).

The kingdom of God is also like "leaven that a woman took and hid in three measures of flour, until it was all leavened" (Luke 13:21). Once leaven is added to flour, it cannot be removed. As the woman stirs the mixture, the leaven distributes through the flour until no part of the batch is unaffected. "Three measures" is about fifty pounds, or twenty-three kilograms. That's a lot of dough. Similarly, the world is a big place. It will take time for God's kingdom to reach every tribe and language, but it will get there (Matthew 28:18–20; Revelation 5:9–10).