His disciples asked him what this parable meant, and he said, "It has been granted to you to know the secrets of the kingdom of God, but the others have only parables, in order that they may look, but see nothing, hear but understand nothing."
This is what the parable means:
The seed is the word of God.
Those along the footpath are men who hear it, and then the Devil
comes and carries off the word from their hearts for fear they
should believe and be saved.
The seed sown on rock stands for men who receive the word with
joy when they hear it, but have no root. They are believers for
awhile, but in the time of testing they desert.
That which fell among thistles represents those who hear, but their
further growth is choked by cares and wealth and the pleasures of
life; and they bring nothing to maturity.
But the seed in good soil represents those who bring a good and
honest heart to the hearing of the word, hold it fast, and by their
perseverence yield a harvest."