Interpreting the parables
Mark 4:10-12 falls between the telling of the parable of the sower (Mark 4:1-9) and its explanation (Mark 4:13-20).
In these verses, Jesus explains why he used parables to teach. Parables act as a filter, because the amount gleaned varies according to whether the hearer wishes to put the teaching into practice or not. Merely listened to with disinterest, they will remain at arms length; however, the person who wishes to live out what Jesus teaches will understand them enough to do so.