13:31-35 The scope of the parable of the seed sown, is to show that the beginnings of the gospel would be small, but its latter end would greatly increase; in this way the work of grace in the heart, the kingdom of God within us, would be carried on. In the soul where grace truly is, it will grow really; though perhaps at first not to be discerned, it will at last come to great strength and usefulness. The preaching of the gospel works like leaven in the hearts of those who receive it. The leaven works certainly, so does the word, yet gradually. It works silently, and without being seen, Mr 4:26-29, yet strongly; without noise, for so is the way of the Spirit, but without fail. Thus it was in the world. The apostles, by preaching the gospel, hid a handful of leaven in the great mass of mankind. It was made powerful by the Spirit of the Lord of hosts, who works, and none can hinder. Thus it is in the heart. When the gospel comes into the soul, it works a thorough change; it spreads itself into all the powers and faculties of the soul, and alters the property even of the members of the body, Ro 6:13. From these parables we are taught to expect a gradual progress; therefore let us inquire, Are we growing in grace? and in holy principles and habits?

42. And shall cast them into a furnace of fire—rather, "the furnace of fire":

there shall be wailing and gnashing of teeth—What terrific strength of language—the "casting" or "flinging" expressive of indignation, abhorrence, contempt (compare Ps 9:17; Da 12:2): "the furnace of fire" denoting the fierceness of the torment: the "wailing" signifying the anguish this causes; while the "gnashing of teeth" is a graphic way of expressing the despair in which its remedilessness issues (see Mt 8:12)!