Now the parable is this: The seed is the word of God.

Matthew Henry's Concise Commentary

8:4-21 There are many very needful and excellent rules and cautions for hearing the word, in the parable of the sower, and the application of it. Happy are we, and for ever indebted to free grace, if the same thing that is a parable to others, with which they are only amused, is a plain truth to us, by which we are taught and governed. We ought to take heed of the things that will hinder our profiting by the word we hear; to take heed lest we hear carelessly and slightly, lest we entertain prejudices against the word we hear; and to take heed to our spirits after we have heard the word, lest we lose what we have gained. The gifts we have, will be continued to us or not, as we use them for the glory of God, and the good of our brethren. Nor is it enough not to hold the truth in unrighteousness; we should desire to hold forth the word of life, and to shine, giving light to all around. Great encouragement is given to those who prove themselves faithful hearers of the word, by being doers of the work. Christ owns them as his relations.