He put before them another parable: “The kingdom of heaven is like a mustard seed that a man took and planted in his field. Although it is the smallest of all seeds, yet it grows into the largest of garden plants and becomes a tree, so that the birds of the air come and nest in its branches.”
Someone who has followed Jesus for six months can still lose their temper over a parking space and drive home wondering whether anything has really changed. The old habits are still there, and the same worries still turn up at three in the morning.