By his amazement in this verse, he is not suggesting that the other parables are more difficult, but rather that one needs particularly the receptive and processive attitude (that the parable of the sower deals with) for all the other parables. In a certain sense, this parable contains the hermeneutical key for the others (Listen! If you have ears to hear, listen! Receive and process Jesus’ words just as the good soil received the seed!).1
13 And he said to them, “Do you not understand this parable? How then will you understand all the parables?