The disciples made a perfectly reasonable request. “Increase our faith.”

They didn’t just say this out of the blue. You know, like sitting around talking about the weather or fishing or how lousy Mary Magdalene’s matzo ball soup is and then suddenly blurting out, “Hey, could you pass the salt and a little more faith, please?”

Nope. Jesus had been teaching them some demanding stuff about what it means to walk in the way of love. For instance, you have to confront people when they’ve gone off the rails. Only, you have to do it lovingly. Willing to forgive and ready to mend fences. Not just once but over and over and over again.

That’s a tall order. So, they said, “Increase our faith.” My sense is that they meant something like, “Teach us how to do this and give us the gumption to do it.”

And then, Jesus goes all Zen Master on them. He tells them a bizarre parable. Stare at that parable as long as you like, but you’re not going to find any explicit instructions about how to forgive or any precise concepts about God.

At this point in their time with Jesus, the disciples wouldn’t have been surprised. Frustrated and confused, maybe. But not surprised. They’ve learned that parables don’t convey information by analogy. They stretch our souls by loosening our grip on what we feel so certain about.

Our thinking about God is not the same thing as really experiencing God in our lives. Paradoxically, by focusing on doctrines and piling up Bible passages we can actually avoid embracing the life-transforming presence of our Redeemer.

We can be so sure of who God is that we never stop to look and listen, I mean really look and listen, to what God is up to in our lives and in the world around us.

Face it, we are finite. God is infinite. As one of my philosophy students used to put it, we are small and God is really, really big. Nothing we ever think or imagine or say about God adequately captures who God is. And besides, God is a who, not a what. Knowing and loving a who is always a work in progress. We never get to the bottom of another person, especially a divine one.

As Henry David Thoreau once said, “When any real progress is made, we unlearn and learn anew what we thought we knew before.” Or, to paraphrase the contemporary theologian Peter Enns, faith is not about certainty.

If you want to grow in faith, you’re going to have to let go of being so sure that you’re right. That’s what Jesus was getting at in the parable of the mustard seed. Jesus says that with faith the size of a mustard seed you will be able to tell a mulberry tree to hike up its roots and plant itself in the sea.

Initially this may sound as if Jesus is simply scolding them for their puny faith and telling how much they could accomplish with more faith. But what an odd response to their sincere request for help to become better disciples. It’s not very, well, Jesus-y.

Look more closely at the parable. Jesus tells them that in the faith-infused universe they’ll be able to order plants around and that ordinary trees will start growing out of the deep blue sea. After uprooting themselves and scrambling to the sea on their little plant feet.

This is nuts. It’s just not how things work. And that’s precisely the point. The first step in spiritual growth—in genuine faith formation—is giving up the idea that faith is about what you know.

For us in the 21st Century this is especially crucial. We inherited Francis Bacon’s dictum that knowledge is power. The experimental method of the natural sciences relies on the ability to predict and control. Get that? Control. Knowing is about our power to control a world of things.

Faith isn’t about knowing things. It’s about trusting a person. A divine person. Trusting that God will be faithful to us. Really be God—the God who is love through and through—no matter what.

Since visiting the concentration camp in which my then-fifteen-year-old mother suffered unimaginable terror and brutality, I’ve been thinking a lot about certainty and uncertainty.

I’m certain that I’ll fall if I stumble off a ladder and that I’ll suffocate without oxygen. But that kind of stuff isn’t what makes life worth living. I need to know it to survive, but it’s not going to get me out of bed in the morning much less motivate me to turn the other cheek and love my enemy.

No, the big things are more like this:

Does love really make a difference in this world?

Will my life have mattered?

Will suffering and sacrifice and sorrow be redeemed?

Does God really know everything about me and still love me?

I’m not certain about any of this. But I believe. I trust. And that is the way of faith.