He said therefore, “What is the kingdom of God like? And to what should I compare it? It is like a mustard seed that someone took and sowed in the garden; it grew and became a tree, and the birds of the air made nests in its branches.”

–Luke 13:18-19

Do you remember the first time you climbed up into a tree so you could peer into a bird’s nest? Jesus tells us to “consider the birds” (Luke 12:24), and that may be the first of his instructions that we follow.

My sons watched for months as a mother bird tended to three eggs in a nest just outside their bedroom window. They were captivated.

A bird’s nest curiously contradicts a bird’s identity. Birds fly. Flight is really their only defense mechanism. When a threat approaches, they fly. Birds are impermanent by nature. But a nest is the opposite. It is permanent. A nest is the one play a bird risks staying put. And it is a risk.

How many times have you found a nest on the ground? Perhaps it was knocked out of the tree by wind, rain, or a neighborhood cat. Nests cannot fly like the birds that build them. They are vulnerable.

When Jesus mentions a mustard seed we tend to think of other passages initially. That one about faith as small as a mustard seed moving entire mountains (Matt. 17:20). Or perhaps you think of the mustard-seed-sized faith that can uproot mulberry trees (Luke 17:6).

This mustard seed is different though.

In this parable, the kingdom of God is still described as a mustard seed, something very small that grows into something big—a tree. But if we don’t consider the birds, we’ve missed the point of this parable. The kingdom of God isn’t just something small that grows large. It’s a tree where birds come to build their nests.

The idea isn’t original to Jesus. He is so thoroughly biblical that Scripture oozes out of him. Ezekiel was the first to talk like this:

This is what the Sovereign Lord says: “I myself will take a shoot from the very top of a cedar and plant it; I will break off a tender sprig from its topmost shoots and plant it on a high and lofty mountain. On the mountain heights of Israel I will plant it; it will produce branches and bear fruit and become a splendid cedar. Birds of every kind will nest in it; they will find shelter in the shade of its branches.” (Ezek. 17:22-23)

Some people have problems with the “God of the Old Testament” because his God picks one people (Israel) at the expense of all other people. But anyone who really reads their Old Testament, or listens to Jesus, knows that God chooses one people for the sake of all people. God has always intended the kingdom to be a tree where “birds of every kind” build their nests.

If the parable of Luke 13:18-19 still doesn’t make sense, we should do what good Bible students do and read around the parable. When we do, we find the fascinating story of a crippled woman whom Jesus heals.

She just “appears” (Luke 13:11), much like a bird, while Jesus is teaching. The text tells us she is “bent over” (13:11), and has been for 18 years. By nature of her condition, she is always overlooked. This is proven by the fact that, unlike other wounded people in the Gospels, she has no one to help her reach Jesus. She is on her own.

When I read her story, I picture a mother bird bouncing from limb to limb, tree to tree, trying to find a place safe enough to build her nest. For 18 years, she hasn’t found the tree.

But then “Jesus saw her” and “called her over” (13:12). Don’t rush by that. Jesus doesn’t just heal her. He first sees and welcomes the woman whom no one else has seen and welcomed for 18 years (see 13:14). In doing so, he proves that he is the safe place she has been longing for. She can land with him.

Then he describes the kingdom of God as a tree where the birds of the air build their nests.

Maybe it’s this simple: the kingdom of God is the safest people to build your nest among. Okay, there is more to it than that. This is only one parable. Only a partial description of God’s kingdom. But it is a significant piece.

Jesus is open to people. He is hospitable. He sees the ones no one else sees, and he welcomes them to himself. They feel safe with him. They stay put because of that, even though doing so makes them vulnerable. They trust him with their vulnerabilities.

So perhaps a measure of the kingdom of God in our lives is the extent to which we are like Jesus. Ask yourself this: Am I hospitable? Am I welcoming? Am I safe? Am I trustworthy? Can others be vulnerable with me? Am I growing into a tree in which the birds of the air would feel safe building their nests? Or am I the kind they fly away from?

I had a professor at ACU who always worked with his door open and his desk facing that open doorway. Efficiency experts will tell you this is a terrible idea. You’ll never get any work done. But he insisted on this because it was his practice to stop whatever he was doing when anyone—from the president of the university to a first-year student—stopped by. He would see them, lay down his laptop, and smile widely as he approached with a hand extended. He would say, “Take a seat. Tell me, what’s on your mind.” And you knew you were safe.

That is the kingdom of God.