Jesus seemed especially fond of using parables. In its form, the ancient Middle Eastern parable is a simile, that is, an explicit comparison of one item to another. Jesus' parables tell his listeners what God is like by comparing God's being or behavior to something familiar and known in the culture.
The reason why parables were and are difficult to interpret is because they point out how things are similar but also different. In other words, God is similar to, yet different from, whatever is presented as the point of comparison.
Kingdom of God
Many parables begin with the phrase “the kingdom of God is like. ... ” The English phrase is unfortunate because Jesus is not describing a place (kingdom) but rather a person (God). Many scholars prefer to translate: “The reign of God is like. ... ” In other words, a parable describes, or presents a scenario that illustrates what happens when God is totally in charge of life.
To understand the parable about the sown seed (Mk 4:26-29), a Western reader must be familiar with a very fundamental, ancient Middle Eastern conviction (common to all peasant societies): “All goods are finite in quantity, that is, limited in number, and already distributed.” In other words, there is no more where this came from.
Any Middle Easterner who suddenly realized an increase in goods was considered a thief, because one peasant's gain usually meant another peasant's loss. Recall how the woman who lost a few coins rejoiced and invited friends to a party that cost more than the value of the rediscovered coins (Lk 15:8-9). It was imperative to demonstrate that she had not stolen the coins from another person or found what someone else had lost.
Yet peasants recognized certain yields, like livestock, a good crop, and children as exceptions. These increases were viewed as imponderable but very welcome gifts from God.
Even so, a limited-good culture expected that anyone who realized a sudden windfall should immediately share it with others rather than store it up for personal use in the future (see Lk 12:16-21). To keep it for one's personal benefit manifested greed.
In Mark’s first parable today, the man is ignorant and perhaps even slothful. After planting the seed, he does nothing to help it along. He neither tills, weeds, nor irrigates the crop.
Yet the earth itself brings forth the harvest.
What is God's reign like? If it depends upon human effort, one risks failure. If humans choose to trust God instead of relying upon themselves, unimaginable success can result. The choice is up to the one who hears the parable.
This parable presents a slight variation on the previous one. Mark makes the parable botanically correct: the mustard seed becomes a shrub, sometimes rather large, but it never grows into a tree (see Lk 13:19). Yet Mark notes that the shrub has large branches and that birds can make nests in its shade.
The listener is challenged to imagine how great the kingdom will be: will it be small and selective, only admitting a few? or will it look small (like a shrub) but actually be largt enough to shelter varieties of birds?
The choice is up to the listener.
The puzzling remark about Jesus teaching the crowds in parables but explaining things in private to his disciples casts the parables into yet another light. To appreciate this, a reader needs to understand the importance of secrecy in the ancient Mediterranean world.
Honor requires that outsiders should learn nothing damaging about insiders. Hence, secrecy is an important strategy for family groups. Yet it is also socially unacceptable because others will suspect that those who keep secrets are plotting to damage their honor. A troubling dilemma.
Jesus' parables spoken to the public (the outsiders) carry one meaning, but explained to his disciples (the insiders) carry another (e.g., compare the interpretation in Mk 4:10-20 to the parable in Mk 4:1-9).
Should the believer settle for the outsider interpretation or strive to gain the insider understanding? The choice is up to the listener!