In gardening "volunteer" is a term we use to describe plants that come up on their own. These are plants you likely would have planted, that you want in your garden, but they just beat you to the punch.
This summer I had several volunteer tomato plants from a particularly voracious variety. I had so many volunteers I snagged most of them up and gave them out to my friends. Those little suckers produce HUNDREDS of little cherry tomotoes. In fact, the plant that came up first is now the biggest thing in my garden (save two enthusiastic cantaloupes). It could definitely be more accurately described as a bush, rather than a plant. It's so prolific I don't even bother to fight off the hornworms (who can take off a whole stem in an hour). I figure there's enough to go around, even for the pests.
All I've had to do is water and it has overwhelmingly blessed me in gratitude. I remind you, I DID NOT PLANT THIS THING. I didn't purchase the seeds. I didn't start it early. I don't even weed around it. In fact, it's not even in my garden, it's in the gravel next to my garden.
What if the Holy Spirit is working like this in the world around us? All we have to do is come alongside and water. My tomato plant surprised me with joy. It's feeding my family AND my neighbors, friends, and the free pantry at church. I believe God is just this good, working subtly, secretly, steadily, regardless of my participation. If I join in, what incredible work might I get to be a part of?