What the Bible Says About Faith
The short answer
When people search for bible verses about faith, they often want to know how to get more of it — as if faith were a substance you could stockpile. Jesus quietly undoes that assumption. In Matthew 17:20 he tells his disciples that faith "as a grain of mustard seed" is enough to move a mountain. The point is not that a mustard seed is impressively small; it's that size was never the measurement that mattered. Faith works not because of how much of it you have, but because of who it is placed in.
N. T. Wright puts it with a memorable picture: if you want to see the moon, what matters is not how big your window is but which way it faces. A narrow slit on the right side of the house will show you the moon; a grand window on the wrong side shows you nothing. Faith is like that. A small, honest prayer to the true God accomplishes more than elaborate devotion aimed in the wrong direction.
Jeremiah supplies the sober other half of the picture. In Jeremiah 12:2, the prophet describes people who flourish outwardly and say all the right religious words — God is "near in their mouth" but "far from their heart." As John Goldingay observes, this was a community that professed loyalty, showed up to worship, made the correct confessions, and sang the right hallelujahs, all while their lives told another story. Put these two passages together and a definition emerges: biblical faith is neither a quantity to be measured nor a performance to be polished. It is genuine orientation — a life actually turned toward the true God, however small and unimpressive the turning may look from outside.
What scholars say
N. T. Wright answers the question of whether faith needs to be big to work, using the image of a window facing the moon: what matters is direction, not size. John Goldingay then shows the flip side in Jeremiah — a community that made the right confessions and sang the right hallelujahs while God remained near only in their mouths.
“The secret, of course, is that the size of the faith isn’t important; what’s important is the God in whom you believe. If you want to see the moon, the size of the window you’re looking through isn’t important; what matters is that it’s facing in the right direction. A tiny slit in the wall will do if the moon is that side of the house. A huge window facing in the wrong direction will be no good at all. That’s what true faith is like. The smallest prayer to the one true God will produce great things; the most elaborate devotions to a ‘god’ of your own making, or indeed someone else’s, will be useless, or worse.”
“He is concerned about his particular faithless community, the people of Anathoth. Jeremiah continues to use the language of Ps 1 ("plant," "root," "fruit") with some irony, and also again picks up language from the account of his commission. Future planting was where Yahweh ended in 1:10. Here he begins with past planting: You have planted them (2:21; 11:17). And they have rooted and produced fruit as he intended (2:7; 7:20; 11:16), though apparently in a rather ironic sense (see 6:19). To say they have produced fruit is another way of saying that they have flourished—but not in a good sense. The problem is that you are near in their mouth in that they profess faithfulness to Yahweh, come to worship, make the right confessions, and sing the right hallelujahs.”
What it means for you
This is freeing news for anyone who feels their faith is too small, too shaky, or too quiet. You don't need to manufacture more intensity; you need to make sure you're facing the right way. A short, honest prayer offered to the true God counts for more than any amount of religious polish. At the same time, Jeremiah's warning invites an honest check: is God near only in my mouth — in what I say, sing, and post — or near in how I actually live? Start small. Pray plainly. Let your ordinary weekday choices face the same direction as your Sunday words.
In context
The mustard-seed saying comes in Matthew 17, just after the disciples fail to heal a demon-troubled boy and ask Jesus why. His answer redirects them from the amount of their faith to its object. Jeremiah 12 belongs to the prophet's complaint about his own faithless community, the people of Anathoth. Building on the planting-and-fruit language of his call in chapter 1, Jeremiah describes people God has planted, who have rooted and flourished — but whose apparent success masks hearts far from the God their mouths keep naming.