Verses 31,32. See also Mr 4:30-32. The kingdom of heaven. See Barnes "Mt 3:2".
It means here either piety in a renewed heart, or the church. In either case the commencement is small. In the heart, it is at first feeble, easily injured, and much exposed. In the church, there were few at first, ignorant, unknown, and un- honoured; yet soon it was to spread through the world.
Grain of mustard seed. The plant here described was very different from that which is known among us. It was several years before it bore fruit, and became properly a tree. Mustard, with us, is an annual plant; it is always small, and is properly an herb. The Hebrew writers speak of the mustard-tree as one on which they could climb, as on a fig-tree. Its size was much owing to the climate. All plants of that nature grow much larger in a warm climate, like that of Palestine, than in colder regions. The seeds of this tree were remarkably small:; so that they, with the great size of the plant, were an apt illustration of the progress of the church, and of the nature of faith, Mt 17:20.
Young converts often suppose they have much religion. It is not so. They are, indeed, in a new world. Their hearts glow with new affections. They have an elevation, an ecstasy of motion, which they may not have afterwards—like a blind man suddenly restored to sight, The sensation is new, and peculiarly vivid. Yet little is seen distinctly. His impressions are indeed more vivid and cheering than those of him who has long seen, and to whom objects are familiar. In a little time, too, the young convert will see more distinctly, will judge more intelligently, will love more strongly, though not with so much new emotion, and will be prepared to make more sacrifices for the cause of Christ.