The kingdom of heaven is like a mustard seed that a person took and sowed in a field.
The parable of the mustard seed follows after two other seed-based parables which emphasize the tribulations which the Gospel must endure. The first, which was read by the Church last Sunday, is of the sower who went forth to sow – of the seed which he scattered, three parts were lost (for they fell upon the path, the rocky earth, and among thorns), and only one part was preserved (for it alone fell upon the good soil).
Our Lord then proceeds with another parable which emphasizes an additional tribulation. In the parable of the weeds and the wheat, we learn that even among the seed placed in good soil, the enemy will come and sow weeds which will threaten the wheat and attempt to stifle the harvest.
Hence, when he comes to the third parable, that of the mustard seed, Fr. Cornelius a’ Lapide begins his commentary on this passage with the following remark: “This is Christ’s third parable, the occasion and cause of which St. Chrysostom gives as follows: ‘Because the Lord had said that of the seed three parts perish, and one is preserved, and again of that which is preserved, there is great loss on account of the tares which are sown above it, lest people should say, who then and how many will believe? He removes this fear by the parable of the grain of mustard seed, and therefore it is said, Another parable put He forth unto them, the kingdom of Heaven is like unto a grain of mustard seed, et c.’”
As the Fathers and Doctors interpret this passage, they see Christ himself, the Church, and even St. Lawrence the deacon represented in the tiny seed which grows to become a great plant.
Jesus Christ, the Mustard Seed
[from Fr. Cornelius a’ Lapide’s commentary on the passage]
You will enquire in the first place, what it is which is here compared to the kingdom of Heaven, and likened to a grain of mustard seed?
St. Hilary understands it of Christ Himself. He says, “The Lord compares Himself to a grain of mustard seed, which is very sharp and the least of all seeds, and whose virtue and power are increased by bruising and pressure. After this grain had been sown in the field, when it was taken by the people and delivered to death, as though in a field by a sort of sowing, there was the burial of its body, it grew above the measure of all herbs, and exceeded the glory of all the prophets. For like a herb the preaching of the prophets was given to Israel as being sick: but now in the branches of the tree, raised from the ground on high, the birds of the air dwell: by these we understand the Apostles, lifted up by the power of Christ, and they overshadow the world with their branches. To them the Gentiles flew for the hope of life; and when they are vexed with whirlwinds, that is by the blasts of the devil, they rest as in the branches of a tree.”
In like manner St. Gregory (lib. 19 Moral. c. 11.) expounds this whole parable, “Christ Himself is the grain of mustard seed, who was planted in the sepulchre of the garden, and rose again a mighty tree. He was but a grain when He died; a tree when He rose again. A grain through lowliness of the flesh; a tree by the power of His majesty. A grain, because we saw Him, and there was no comeliness; but a tree because He was fairer than the children of men. The branches of this tree are sacred preachers. And let us see how widely they are spread. For what is spoken concerning them? Their sound is gone out into all the earth, and their words unto the end of the world. The birds rest in their branches, because holy souls who lift up themselves from earthly thoughts by the wings, as it were, of virtues are refreshed after the fatigue of this life by their words and their consolations.”
You will say, how can Christ be called the kingdom of Heaven, when He is not the kingdom, but its King? It is replied: as a king is as it were the head in a kingdom, so a kingdom is as the body of a king. Wherefore a king represents the whole state or kingdom. Hence according to the rule of Ticonius, often in Scripture what belongs to the Church, which is the kingdom of Christ, is attributed to Christ, and vice versa.
The Primitive Church symbolized by the mustard seed
Consider the commentary from the Navarre Bible: “Here, the man is Jesus Christ and the field, the world. The grain of mustard seed is the preaching of the Gospel and the Church, which from very small beginnings will spread throughout the world. The parable clearly refers to the universal scope and spread of the Kingdom of God: the Church, which embraces all mankind of every kind and condition, in every latitude and in all ages, is forever developing in spite of obstacles, thanks to God’s promise and aid.”
St. Lawrence compared to the mustard seed
Finally, we return to Fr. Corneilus a’ Lapide who cites St. Augustine in comparing the mustard seed first to the Christian soul and then to St. Lawrence the holy Roman deacon and martyr:
“All these things may be applied to a faithful soul, and especially to an Apostle, and to a suffering Christian, or to a martyr. Wherefore the Church adapts this parable to St. Laurence, as the Gospel for his festival. As St. Augustine says, in the work already cited [Serm. 33 de Sanc.], ‘We may compare the holy martyr Laurence to a grain of mustard seed; for he, being bruised by various sufferings, deserved to become fragrant throughout the whole world by the grace of his martyrdom. He, when he was in the body, was humble, unknown, and held in low estimation; but after he had been bruised, torn, and burnt he diffused the odour of his nobleness in the churches in all the world. Rightly, therefore, is the comparison applied to him. For Laurence, when he suffers, is inflamed. The fervour of its attrition moves the one; Laurence breathes forth fire in his manifold tribulations. Mustard, I say, is cooked in a small vessel; Laurence is roasted on the gridiron by the fiery flame. Blessed Laurence the martyr was burnt outwardly by the flames of the raging tyrant, but he was inflamed inwardly by the far greater fire of the love of Christ.’
“The Arabians have a proverb—‘A grain of pepper is more powerful than many large gourds;’ because if it be bruised it emits a fiery force, and makes itself felt in everyone’s nostrils. You may say the same of a grain of mustard. A believer, therefore, should be a grain of pepper or mustard, and breathe everywhere, and upon all, a divine fire, and so pepper all men, and make them like himself, zealous that is, and ardent in the love of God.”