What Jesus said about faith
A mustard seed — and why he talks about size, not strength.
Most of what gets said about faith today is about intensity: believing harder, doubting less, holding on. Almost none of that language is his.
When Jesus talks about faith he talks about quantity, and the quantity is always comically small. That is a different idea, and a more usable one.
Where he taught it
- Matthew 17:20Faith the size of a mustard seed, and the mountain
- Matthew 8:10A Roman officer, and the only faith he calls great
- Matthew 14:31Peter on the water: "why did you doubt?"
- Luke 17:6The mustard seed again, with a mulberry tree
- Mark 11:22–24Faith and asking, in the same breath
- John 20:29To Thomas: those who have not seen
One of them, with the room around it
if you have faith as a grain of mustard seed, you will tell this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you.
He had just come down from a mountain to find his own disciples unable to help a boy, and a crowd watching them fail. The sentence is spoken into that embarrassment. He does not tell them to believe harder — he tells them the required amount is the smallest seed they could name, which means the problem was never the quantity.
What runs through them
The person he singles out for great faith is a Roman officer — an outsider, with no religious standing, who simply took him at his word about something practical. That is the model, and it is unspectacular.
Nowhere does he describe faith as certainty. The closest he comes is the opposite: when Thomas demands evidence, he supplies it. Faith in his teaching looks much more like acting on something before it has been proved than like feeling sure.
The whole collection, one day at a time
Walking with Jesus: Devotional has a collection called Jesus on Faith that walks these teachings one a day, each with the passage around it, a reflection, a prayer and one thing to carry into the day.
A one-time purchase, about five minutes a morning.
Questions people ask
- What did Jesus mean by faith like a mustard seed?
- He said that faith the size of a mustard seed — the smallest seed his listeners would have handled — was enough to move a mountain (Matthew 17:20). The image is about how little is required, not about how strongly you must believe.
- Is doubt the opposite of faith?
- Not in the Gospels. Jesus answers Thomas’s demand for evidence by giving it to him (John 20:27), and the disciples closest to him are repeatedly described as doubting without being cast out. Indifference sits further from faith than doubt does.
- Whose faith did Jesus call great?
- A Roman centurion’s, in Matthew 8:10 — a foreign soldier who said Jesus need not come to his house, a word would do. He had no standing in the religious community of the time.