Mark 4:30-33 (ESV)
30 And he said, “With what can we compare the kingdom of God, or what parable shall we use for it? 31 It is like a grain of mustard seed, which, when sown on the ground, is the smallest of all the seeds on earth, 32 yet when it is sown it grows up and becomes larger than all the garden plants and puts out large branches, so that the birds of the air can make nests in its shade.” 33 With many such parables he spoke the word to them, as they were able to hear it.
Gospel of Thomas
20. The disciples said to Jesus, “Tell us what Heaven’s kingdom is like.”
He said to them, “It’s like a mustard seed, the smallest of all seeds, but when it falls on prepared soil, it produces a large plant and becomes a shelter for birds of the sky.”
At a popular level within Judaism the mustard seed represented the smallest seed which according to the Mishnah was grown in a field rather than a garden. See Matt 13:31(field) and Luke 13:19 (garden) and Mark/ used the word soil/ground. In fact the mustard seed is neither the smallest of seeds, not does it grow to become the largest plant. But this does not make the story void, the story is not a hard science of botanical study but uses popular analogy to communicate a message,
The parable shows 2 sides to the kingdom. It starts off small but end up large. The kingdom which began in Jesus’ ministry would, according to Jesus’ parable and seen in history since, will spread and become large
he choice of the mustard seed appropriately described the almost infinitesimal presence of God’s rule relative to the popular expectation of the times. At the same time, this dimension did not represent the total picture. A second dimension included the coming of the Kingdom in its greatness. The contrast gives instruction about both dimensions but offers little about the interval in between or the growth process.
Guelich, Robert A.: Word Biblical Commentary : Mark 1-8:26. Dallas : Word, Incorporated, 2002 (Word Biblical Commentary 34A), S. 252
What about he birds who would come and next in in the tree? Their is probably a linguistic echoe of Exekial 17:22-23
Thus says the Lord God: k“I myself will take a sprig from the lofty top of the cedar and will set it out. lI will break off from the topmost of its young twigs a tender one, and mI myself will plant it on a high and lofty mountain. 23 nOn the mountain height of Israel will I plant it, that it may bear branches and produce fruit and become a noble cedar. oAnd under it will dwell every kind of bird; in the shade of its branches birds of every sort will nest.
R.T France offers the following,
But again, as in the previous parable, the simile concludes with an OT echo. The birds nesting33 in the branches are not strictly necessary to the description of the mustard, but serve to recall the imagery of Ezekiel’s cedar-tree parables (Ezk. 17:23; 31:6) and of Nebuchadnezzar’s dream, Dn. 4:9, 18 (EVV 4:12, 21), and the words are close enough to those of the LXX/Thdt in these passages to make the echo unmistakable for those who are familiar with them. Mark’s rather inappropriate mention of the κλάδοι μεγάλοι of the mustard helps to strengthen the allusion, since the great branches are a part of the imagery in these OT figures. Ezekiel’s two cedars and Nebuchadnezzar’s tree represent the growth of impressive empires, and the birds which nest in them are explicitly interpreted in Ezk. 31:6 as ‘all great nations’ who enjoyed the benefits of the Egyptian empire. The allusion here may therefore be intended to indicate the future wide scope of the kingdom of God, within which many nations (not only Israel) will find their place. Even if the nesting birds are no more than part of the imagery of growth and so should not be specifically identified, their OT background reinforces the ‘imperial’ pretensions of the kingdom of God, which will take the place of the human empires of OT times (cf. the use of imagery elsewhere in the synoptic tradition from Dn. 2 and 7, two memorable visions of a new kingdom to replace the pagan empires).
France, R. T.: The Gospel of Mark : A Commentary on the Greek Text. Grand Rapids, Mich.; Carlisle : W.B. Eerdmans; Paternoster Press, 2002, S. 216
Israel were called to be a blessing to the nations. They in one sense had failed and at least some 1st century Jews were stringly influenced by a Zealot ideology and a posture of agression against the Romans.With the arrival of the kingdom of God, in the life and work of Jesus, this calling has again been put on the agenda. Instead of destruction coming to the pagan nation.s a offer off refuge, in the tree of the kingdom of God, is being offered.
Do we accept the missional call of the kingdom? Are our Christian communities lights to the nations, do the nations come to us for wisdom, guidance and refuge?