Final answer:
The kingdom of God is compared to a mustard seed, which starts small but grows into a large tree, symbolizing the growth of God's kingdom.
Step-by-step explanation:
The kingdom of God is compared to a mustard seed that grows into a big tree. The mustard seed is recognized for its small size, yet it grows into a large tree, which is symbolic of how something small and seemingly insignificant can grow into something great and majestic within the kingdom of God. This comparison is often used to illustrate the potential of faith and the growth of God's kingdom in the world.