The Parable of the Mustard Seed
The parable of the mustard seed and the following parable of the leaven are closely related. Together they show us something of the historical development of the kingdom of heaven. The parable of the mustard seed speaks of the outward development of this kingdom, while the parable of the leaven focuses more on its inward development. Both are very instructive, but often misunderstood. This article considers the former parable.
‘Another parable set he before them, saying, The kingdom of the heavens is like a grain of mustard seed which a man took and sowed in his field; which is less indeed than all seeds, but when it is grown is greater than herbs, and becomes a tree, so that the birds of heaven come and roost in its branches’ (Matt. 13:31–32).
The mustard seed
The Lord Jesus uses an illustration to explain the outward development of the kingdom of heaven. The field is the world (v. 38). The man who sowed is the Lord Jesus. The black mustard seed is tiny and insignificant and therefore an appropriate illustration of the beginning of the kingdom in its present form as viewed from the outside. It began with only a few people — just the 11 disciples, who had followed the Lord Jesus, plus around 120 believers who were with them in the upper room (Acts 1). Afterwards, we see how the gospel spread and many accepted the Lord Jesus and became part of that kingdom.
However, the Lord Jesus then speaks of a development which does not correspond to what occurs in nature. The black mustard seed does not grow into a big tree. It grows no further than a bush, and certainly not into a tree in which birds build their nests. Of course, the Lord Jesus knew this very well so He drew this illustration with a special purpose behind it. The teaching is hidden in the contrast between what occurs in nature and what He describes.
A great tree
The Lord Jesus wants to make it very clear from the outset that the kingdom — viewed from the outside — would grow in an unnatural way and become a great thing in the world (the field). It took less than 300 years before the emperor Constantine the Great (AD 272–337) declared Christianity to be the official religion in the Roman Empire. That was the very reason why many professed to become Christians but without having new life. They were Christians in name only — there was no reality behind it. This is true of many even today. The Apostle Paul speaks of those who have ‘a form of piety but denying the power of it’ (2 Tim. 3:5).
Many modern theologians consider the development of which we read in this parable as something positive. They are wrong — the very opposite is true. They overlook the true teaching of this parable. Although the work was started by the Lord Jesus Himself (He is the sower who sowed the mustard seed), it was soon spoiled by the activities of others. That a tree that becomes great is something negative is confirmed by other examples in the Bible. For example, in Daniel 4, Nebuchadnezzar, the mighty king of Babylon is illustrated by a tree, but in a negative way. Another example is in Ezekiel 31 where Assyria is compared to a great tree. A mighty tree symbolizes great authority and political power, which can easily be misused (as has sadly occurred in the history of the Christian profession).
This helps us to understand the meaning of the Lord’s teaching in this parable. The first Christians were like a mustard seed. In the beginning, they were but a small group in Jerusalem. Later on, they were scattered abroad in the Roman Empire. They were despised, rejected and persecuted. But step by step the situation changed and, as already mentioned, Christianity became the official religion in the empire. This helped to spread Christianity outwardly, but — alas — many of those who call themselves Christians are only Christians in name.
Was this development according to God’s idea? Surely not. We are left here in the world as witnesses but also as those who are (or should be) ‘unknown’ by the world (2 Cor. 6:9). Our citizenship is not on earth. We are a heavenly people with a heavenly calling and a heavenly home. The time to rule will come (Rev. 20:6), but in the present phase of the kingdom this is not yet so (1 Cor. 4:8). For us the kingdom now is characterised by suffering (Acts 14:22).
The birds of heaven
That the development of the kingdom, viewed from the outside, is negative is confirmed by the reference to the birds of heaven. Birds have different meanings in the Bible. Sometimes they are a symbol of judgment (e.g. 1 Ki. 14:11); other times of many nations (e.g. Ezek. 17:23). But they also speak of evil and satanic influences (e.g. Gen. 15:11; Jer. 5:27). It is clear this must be the significance of the birds in our parable.
We see them in verse 4, and the Lord Jesus Himself explains their significance in verse 19. They speak of evil and satanic influence that becomes evident in erroneous teaching. Revelation 18:2 confirms this: ‘And he cried with a strong voice, saying, Great Babylon has fallen, has fallen, and has become the habitation of demons, and a hold of every unclean spirit, and a hold of every unclean and hated bird’. In the symbolic language of the last book of the Bible, Babylon speaks of that part of Christianity that will be left on earth after the rapture — mere professors. Their evil influence will then be unhindered. However, it is already present in Christendom.
Indeed, if we consider the history of the Christian profession, it becomes very clear how many wrong, evil and even satanic teachings have been held and spread by those who call themselves Christians.
An irreversible development
What is our reaction to this development? Are we supposed to accept it or instead to seek to change it? Insofar as the assembly is concerned, we are told expressly to deal with evil and to put it out: ‘Remove the wicked person from amongst yourselves’ (1 Cor. 5:13). However, when it comes to the kingdom, things are different. Already in the preceding parable in Matthew 13:30, the Lord had said: ‘Suffer both to grow together unto the harvest, and in time of the harvest I will say to the harvestmen, Gather first the darnel, and bind it into bundles to burn it; but the wheat bring together into my granary’. The parable of the mustard seed gives no indication at all that we should stop the growth of the tree or drive away the birds. There is no instruction to try to stop the negative developments in the kingdom. What we must do is to keep ourselves undefiled. Personally, we must abstain and separate from evil (2 Tim. 2:21). In this, we should be faithful until the Lord returns for us.
 The mustard seed in the area of the Mediterranean Sea is indeed about ten times smaller than those in more northerly latitudes. Also, in Matthew 17:20 the mustard seed is compared with something that is very small.
 And not only this: Christianity played (and still plays) an important active role in political decisions. You will find this also in the historical outline of Christianity in Revelation 2 and 3, particularly in the letters to Pergamos and Thyatira.
 Although today other religions are growing faster, Christianity is still the most widespread religion in the world (followed by Islam, Hinduism and Buddhism).