From Commentary on Matthew, Mark, and Luke (1555)

By these parables Christ encourages his disciples not to be offended and turn back on account of the meager beginnings of the Gospel. We see how profane men haughtily despise the Gospel, and even turn it into ridicule, because the ministers by whom it is preached are of slender reputation and of low rank or because it is not instantly received with applause by the whole world or because the few disciples whom it does obtain are, for the most part, men of no weight or consideration and belong to the common people. This leads weak minds to despair of its success, which they are apt to estimate from the manner of its commencement.

On the contrary, the Lord opens his reign with a feeble and despicable commencement, for the express purpose, that his power may be more fully illustrated by its unexpected progress… The kingdom of God is compared to a grain of mustard, which is the smallest among the seeds, but grows to such a height that it becomes a shrub, in which the birds build their nests. It is likewise compared to leaven, which, though it may be small in amount, spreads its influence in such a manner, as to impart its bitterness to a large quantity of meal.

If this aspect of Christ’s kingdom seems despicable, let us learn to raise our minds to the boundless and incalculable power of God, which at once created all things out of nothing, and every day raises up things that are not, (1 Cor. 1:28), in a manner which exceeds the capacity of the human senses. Let us leave to proud men their disdainful laugh, till the Lord, at an unexpected hour, shall strike them with amazement. Meanwhile, let us not despair, but rise by faith against the pride of the world, till the Lord give us that astonishing display of his power, of which he speaks in this passage.

John Calvin (1509-1564) was one of the most influential theologians of the Protestant Reformation, who served for many decades as the chief pastor of Geneva. He wrote commentaries on most books of the Bible, which were reworked from lectures he gave to theological students. He is commemorated on May 26 or May 28 on the liturgical calendars of several Anglican churches.