31 Another parable put he forth unto them, saying, The kingdom of heaven is like to a grain of mustard seed, which a man took, and sowed in his field: 32 Which indeed is the least of all seeds: but when it is grown, it is the greatest among herbs, and becometh a tree, so that the birds of the air come and lodge in the branches thereof. 33 Another parable spake he unto them; The kingdom of heaven is like unto leaven, which a woman took, and hid in three measures of meal, till the whole was leavened. 34 All these things spake Jesus unto the multitude in parables; and without a parable spake he not unto them: 35 That it might be fulfilled which was spoken by the prophet, saying, I will open my mouth in parables; I will utter things which have been kept secret from the foundation of the world. (Matthew 13:31-35 KJV)
William Burkitt’s Commentary
Our Saviour’s design in this parable is, to shew how the gospel, from small and little, from unlikely and contemptible beginnings, shall spread and increase, fructify and grow up; like a mustard seed, one of the smallest grains, grows up to a considerable tallness; and as a little leaven turns a great heap of meal into its own nature; so the gospel shall spread and increase, nations and countries becoming Christians.
Learn, That how small beginning soever the gospel had in its first plantation, yet, by the fructifying blessing of God, it has had and shall have a wonderful increase.