The ones along the path are those who have heard; then the devil comes and takes away the word from their hearts, so that they may not believe and be saved. And the ones on the rock are those who, when they hear the word, receive it with joy. But these have no root; they believe for a while, and in time of testing fall away. And as for what fell among the thorns, they are those who hear, but as they go on their way they are choked by the cares and riches and pleasures of life, and their fruit does not mature. As for that in the good soil, they are those who, hearing the word, hold it fast in an honest and good heart, and bear fruit with patience.
So in the end, the point of the parable of the soils is not only that your own salvation and fruitfulness hang on how you hear the Word of God, but also the success of how the Word of God spreads in the world depends on how you hear. That is why verse 18 now concludes (drawing the inference directly from verses 16-17) “So take care how you listen.”
Listening – hearing – is a high calling in the Christian church because your salvation hangs on it (verse 12), and your fruitfulness hangs on it (verse 15), and the spread of the light in the world hangs on it (verses 16-17), and in the end the glory of God hangs on it (Matthew 5:16). So (verse 18), “Take heed how you hear.”