Matthew 13:19–22

Let us see, in concrete terms, what it is to be “on the road.” Every road is somehow hard and useless, because it lies under everyone’s feet; none of the seed is heaped into it, but lies on the surface, ready for any birds that want to snatch it. So those who have a hard, packed mind in themselves do not receive the divine seed, but have become a road trampled by unclean spirits — for these are “the birds of the heaven.” By heaven here we mean the air, in which the spirits of wickedness move, by whom the good seed is also snatched and destroyed.

And who are those on the rock? Some hold the faith in themselves without investigation and do not let the mind down into testing the mystery. These have a light, rootless piety toward God. If Christian affairs are carried with a fair wind and no trial storms them, they scarcely keep the faith in themselves then; but when persecution disturbs them, they have a soul unwilling to fight.