Why a Mustard Seed?
"If you have faith as small as a mustard seed, you can say to this mountain, 'Move from here to there,' and it will move. Nothing will be impossible for you." — Matthew 17:20
It mentions the size. But think about it. Most of us have never seen a mustard seed, let alone a mustard plant. Jesus wasn't only talking about how small it is.
Jesus used this seed more than once.
Once for faith: "If you have faith as small as a mustard seed, you can say to this mulberry tree, 'Be uprooted and planted in the sea,' and it will obey you." — Luke 17:6
And once for the kingdom: "The kingdom of heaven is like a mustard seed, which a man took and planted in his field. Though it is the smallest of all seeds, yet when it grows, it is the largest of garden plants and becomes a tree, so that the birds come and perch in its branches." — Matthew 13:31-32
Mark and Luke both tell this parable too (Mark 4:30-32, Luke 13:18-19), so it mattered enough to be remembered three times.
Look at what the plant does. It grows tall, it spreads, and left alone it takes over the garden. And it gives shelter. The birds come to rest in it.
Some days you are the seed. Small, quiet, buried in the dark. Faith that size still counts.
Some days you are the plant. You grow, you spread, and you become shade for someone else.
One plant makes thousands of seeds. One small act of faith can become far more than we ever see.