Matthew Henry's Concise Commentary

4:21-34 These declarations were intended to call the attention of the disciples to the word of Christ. By his thus instructing them, they were made able to instruct others; as candles are lighted, not to be covered, but to be placed on a candlestick, that they may give light to a room. This parable of the good seed, shows the manner in which the kingdom of God makes progress in the world. Let but the word of Christ have the place it ought to have in a soul, and it will show itself in a good conversation. It grows gradually: first the blade; then the ear; after that the full corn in the ear. When it is sprung up, it will go forward. The work of grace in the soul is, at first, but the day of small things; yet it has mighty products even now, while it is in its growth; but what will there be when it is perfected in heaven!