Many commentators have divergent views when it comes to Jesus’ Parable of the Mustard Seed and the Leaven (Matthew 13.31-33). Some see these tales as pictures of the steady growth and influence of the Church; however, it seems they alert us to two more strategies Satan uses to harm the Church in the period between Christ’s first coming and his Second Coming.

The third and fourth parables belong together. Each should help us to understand the other. Of all the parables Jesus told, however, none has produced such diametrically opposed interpretations as these two. On the one hand, most Bible students understand these parables to be about the kingdom’s steady expansion and growth, so that in time it will come to fill the whole world. On the other hand, others see them as warnings against two of the devices the devil will use to corrupt the Church over time. An abnormal and harmful bureaucratic expansion of the Church and the devil’s work of undermining it by the infusion of sin, represented by the yeast. The problem remains because nothing Jesus said either in the parables themselves or elsewhere explains clearly what they mean.

Whatever our interpretation of the parables might be, there is much more theological agreement between people who take these two sides than the interpretations themselves would indicate. To be sure, there is a profound disagreement as to whether the kingdom of God is going to be victorious in this age. Postmillennialists would say yes. Premillennialists would say no. But even here there is a measure of agreement. Both acknowledge that Christians are sent into the whole world with the Gospel – the essence of the Great Commission. Both would agree that there has been an effective and striking growth of Christianity from its small beginnings at the time of Christ’s death to its position as a major world religion today. Both would acknowledge the evils in the Church, which the second explanation highlights.

So, we may begin by realizing that – with the sole exception of whether the Church is to be victorious in the world or only affect a part of it – most of the points any one interpreter would insist on would be accepted by the other side. We can even say that either explanation can be justified in one way or another as fitting into the development of the parables of the Kingdom in this chapter.

But we do have to think of the stories one way or the other. We should lump them together with the second parable that tells of the devil’s work in sowing tares among God’s wheat. Following are reasons for interpreting them so.

First, the growth of a mustard seed into a tree is abnormal. That is, a mustard seed does not grow into a tree; it is a shrub. Those to whom Christ spoke would know that. So, when He spoke of the unusual growth of this seed, His hearers would have been alerted at once to the fact that something in the situation was profoundly abnormal or wrong. If Jesus had wanted to stress the “victorious Church” view, He should have referred to an acorn growing up to be a mighty oak or a cedar seed growing up to be one of the lofty trees of Lebanon.

Secondly, the birds resting in mustard tree branches have already been identified as the devil or his messengers in the first parable. It is true that an element of one parable need not necessarily carry the same meaning in the next, but it would be strange if an element that symbolized evil at the beginning of the chapter carried a totally different meaning just thirteen verses later. Besides, who are the birds who roost in the Church’s branches if not those evil persons whom the devil has sown among believers? If they are not Satan’s people, who they are is unexplained. On the other hand, if the birds are the devil’s followers, then there is an immediate and obvious carry-over into the parable of the yeast, for the yeast would represent the same thing as the birds do in verse 32. The parable of the yeast would just add the thought that the presence of evil is pervasive, not merely in the hierarchical structures of the Church but in its many members and its life.

Third, in nearly all of Old Testament cases, yeast is a symbol of evil. In the sacrificial laws of Israel, it was excluded from every offering to the Lord made by fire. At the time of the feast of unleavened bread, every faithful Jew was to search his home for any trace of yeast and then get rid of it. Just three chapters after this Jesus speaks of the yeast of the Pharisees and Sadducees – their evil influence (Mt.16.12; where He refers to “the teaching of the Pharisees and Sadducees” as leaven). Likewise, Paul described deviation from the truth of the Gospel as Satan’s evil persuasion, adding that believers should beware since “a little leaven leavens the whole lump [batch of dough]” (Galatians 5.9).

Some have argued that yeast is not always a symbol of evil. Sometimes it is simply yeast. But when it has a symbolic meaning, it is nearly always used to represent something evil rather than something good. It is difficult to see how an important and thoroughly understood symbol of evil could be used by Jesus to represent the exact opposite, namely, the blessed impact of His Gospel on the world.

Finally, it is significant that these two parables are bracketed by that of the devil’s work in sowing tares among the wheat (vv.24-30) and Christ’s explanation of that parable (vv.36-43). The structure suggests that they should be taken not as teaching something entirely different from the parable of the tares but as expanding on it.