John Chrysostom — as excerpted in the Catena Aurea on Mark 4:1-20

“(ubi sup.) This, however, the greater portion of the seed is not lost through the fault of the owner, but of the earth, which received it, that is, of the soul, which hears. And indeed the real husbandman, if he sowed in this way, would be rightly blamed; for he is not ignorant that rock, or the road, or thorny ground, cannot become fertile. But in spiritual things it is not so; for there it is possible that stony ground may become fertile; and that the road should not be trodden down, and that the thorns may be destroyed, for if this could not take place, he would not have sown there. By this therefore He gives to us hope of repentance. It goes on, And he said unto them, He that hath ears to hear, let him hear.”