So let's catch some glimpses of the kingdom of God by asking: "What's strange about this parable?"

  

The Mustard Seed
In both the mustard seed and the leaven, what is strange is the sharp contrast between the initial and the final stages of growth. The emphasis is on God's action in the world which is almost imperceptible, but which yields results that belie its unimpressive appearance. The mustard seed, though it is the tiniest of seeds, grows to host the birds of the air so that they find a home in its branches. The leaven, though hidden in the dough, is capable of leavening the whole loaf so that many are fed.

These two parables, according to Douglas Hare, are meant to inspire faith in God as active in the tiny movement initiated by Jesus. "The twin parables challenge the hearer to leave behind the pedestrian, pragmatic everyday world that treats God as irrelevant and enter into a new world in which God is the primary reality" (Hare, 156). Both parables underscore that God's action is real and will, in the fullness of time, come to full fruition.

The mustard seed is an unimpressive metaphor for the kingdom of God. The detail that the birds of the air will nest in its branches is an extravagant overstatement. That detail would better fit a large tree. And, in fact, in the Old Testament, nations with power and influence are described as huge trees in which birds take shelter. The phrase "the birds of the air can make nests in its shade (or branches)" is a clue that connects this parable with several Old Testament passages where trees are used as grand, dramatic metaphors. Israel is depicted as a noble cedar in Ezekiel 17:22-24. "In the shade of its branches will nest winged creatures of every kind." (17:23b). Assyria (Ezekiel 31:6) and Babylonia (Daniel 4:12) are both portrayed using the metaphor of a cedar tree, lofty and proud, in whose branches the birds of the air nested, but whose pride will lead to their downfall. The righteous person who trusts in God is compared to a flourishing tree in Psalms 1:3, 92:13-15, and Jeremiah 17:7-8.

Parables, rather than being simple stories with one point, are complex scenarios that can evoke all kinds of connections, not only with daily life, but also with other texts. So the humble mustard see that becomes a shrub could make us think of God's care for us like a flourishing tree, or it could turn our minds to the fact that the mustard shrub is not going to be like the mighty trees or empires of former times, which grew through military power and violence. Though small and insignificant, the mustard seed is not to be underestimated. Its power to nurture and sustain far exceeds expectations. Mustard seeds are not just a phenomenon of the past; they are sprouting all around us. Jesus himself is a mustard seed, discounted and discarded, entombed in darkness, sprouting to new life, not only for himself, but for all of us who make our nests in his branches.

The strange element here is the widespread, extravagant effect of the mustard seed/shrub compared to its being dismissed and discounted by the world. A cedar of Lebanon, surely, would be a better metaphor for the kingdom of God. Or maybe not. 

The Leaven (Yeast)
Matthew's version of the parable of the leaven (as does Luke's) contains the surprising note that the woman hid the leaven in three measures of wheat flour. This is a huge batch of dough made from approximately 50 pounds of flour! This would be enough bread for over 100 people. We are probably to see here an allusion to Gen 18:6 where Abraham instructs Sarah to prepare cakes from three measures of flour for his heavenly visitors. The quantity of flour in both passages suggests a festive occasion. Perhaps we are to think of the final outcome of God's hidden activity as the Messianic Banquet at which the heavenly Lord Jesus will dine with his people. The fact that human eyes fail to perceive it does not change the fact that God is at work (Hare, 157).