I always like (well, love) talking to Helen Prejean, C.S.J., the anti-death penalty activist and author of Dead Man Walking. She would probably smack me (literally) if she heard me say this, but I think she is one of the few saints I’ve known. Even after a few minutes with her, I always learn something new, or am inspired or challenged.

So it’s not surprising that something she said in our conversation on the latest episode of “The Spiritual Life” podcast brought me up short.

We were speaking about the familiar Gospel image of the seed, in which Jesus compares the growth of the reign of God to a mustard seed. A few years ago, I was with an America Media pilgrimage group on the shore of the Sea of Galilee, where we were surrounded by dozens of waist-high mustard-seed plants. One of the pilgrims came up to me, stuck her forefinger out and said, “Look!” I couldn’t see anything. “Look more closely.”

On her fingertip with a little white dot. “It’s a mustard seed!” she exclaimed. True enough, it was, as Jesus said, the tiniest of seeds. And from that same kind of tiny seed grew the large bushes that filled the shoreline. (They are not the huge trees that one might expect from Jesus’ parable, but the bushes are plenty big.)

I have long understood that the reign of God, and indeed any spiritual venture, must start small—and then grow. And that this growth often happens slowly. Slow growth is part of Jesus’ parables as well. 

But Sister Helen’s insight was that you really don’t  know what the seed was going to turn out to be, or what it would look like precisely. She spoke about her own ministry working against the death penalty. “It unfolds in its own way,” she said. “You can’t lay out a blueprint [and say] ‘Here’s what’s gotta happen,’ and then see your plan unfold. You gotta let it happen organically.”

I found that extremely helpful and, frankly, new. The mustard seed will become a mustard plant, but you don’t know exactly what it will look like. Tall or short? Full or straggly?? Straight or twisty? How like ministry that is! When the team at America started our Outreach L.G.B.T.Q. ministry five years ago, we had zero idea where it was going or what it would look like. And that’s fine!

All this reminded me of something Pedro Arrupe, S.J., the former Jesuit superior general (and current Servant of God), once said when asked, “Where is the Society of Jesus going?” His response: “I have no idea!” In other words, the Spirit is at work. And only the Spirit knows. 

How like our own lives and individual vocations is that image of the mustard seed. We start out—in a marriage, in religious life, in the priesthood or in a certain career—and while we may think we know where we are headed, we don’t, in the end, know what it will “look like.” 

As Sister Helen says, we can plan, but we often can’t, in her words, “lay out a blueprint.”

And isn’t that wonderful to know? To behold? And, most of all, to live out? 

The Rev. James Martin, S.J., is a Jesuit priest, author, editor at large at America and founder of Outreach.