An imaginative watercolor representation of the biblical passage 'Luke 13:18-19', which depicts a metaphorical scene of an individual sowing a mustard seed in a garden. The minuscule seed gradually grows into a large tree, eventually providing shelter for the birds of the sky. The image should emphasize the themes of growth, faith, and altruism found in the scripture. Use vibrant, fluid shades to capture the warmth and life of the garden setting and the transformative visual narrative from tiny seed to bountiful tree.