The Mystery of God’s Kingdom (4:26-29)
The underlying question still facing Jesus’ proclamation of God’s liberating, emancipatory, life-giving Jubilee junket is the obvious one: “How can any of this be more than pie-in-the-sky moonshine. Look at Rome! Somehow, you are telling us, this New Exodus movement will upend the mighty Empire? Get real! That’s not how things work in the real world.”
Jesus turns to the process they know best – sowing and reaping. This most basic and important process, on which their lives depends, is ultimately mysterious and uncontrollable. We do what we can and have learned to do, but even as we reap a harvest we admit that we really don’t know why this is happening. “The earth produces of itself” – Jesus says.
If God is in control and at work according to his will and plan, humans can never foreclose on old hopes or new possibilities surprisingly opening up right in front of their eyes. And this, Jesus implies, is just what is happening in and through him. The harvest of God’s plan for the world through Israel is at hand – however unpromising that may seem at any given moment.
The Manner of God’s Kingdom (4:30-32)
The manner of God’s kingdom requires vision and patience to embrace a small and insignificant beginning and live toward its full realization. In world of tall trees (empire) it takes both to imagine and hope for that small beginning to result in grand ends. In Ezekiel God promises just such a result: “All the trees of the field shall know that I bring low the high tree, I make high the low tree” (17:24).
Large sheltering trees are a symbol in the Bible for political sovereignty (Judg.9:15; Dan.4:10ff.). A small and persecuted dissident movement, like Jesus’, living in the Roman empire knew what such a large sheltering tree was like. And how little its prospects for surviving and thriving in such a situation. And yet, here is Jesus telling them just that!
The smallest of seeds, the mustard seed, could under maximal conditions produce a shrub up to three meters high. Annual growth to that height was unusual. Among garden plants a tree at such height would certainly be noticeable. And provide good branches for birds to perch on. (France, Mark, 216)
Mark concludes with a summary acknowledging again Jesus’ parabolic pedagogy, the different kinds of hearers he faced (the parable of the Sower, vv.13-20), and his private explanation to his disciples. Perhaps a final indirect admonition to readers to test their mode of hearing and seek explanation from Jesus for what puzzles and eludes us.