The mustard seed becomes a great shrub that shelters the birds, recalling ancient images of the tree of life. We’d expect a cedar or a sequoia, but Jesus finds the power of God better imaged in a tiny, no-account seed. It’s not the way we expect divine activity to look. Yet the tree of life is here, in the cross around which we gather, the tree into which we are grafted through baptism, the true vine that nourishes us with its fruit in the cup we share. It may not appear all that impressive, but while nobody’s looking it grows with a power beyond our understanding.