On another occasion, Jesus began to teach...Mark the evangelist reminds us, in case we had forgotten, that Jesus is also a teacher. He does work miracles and performs signs, but he is also a teacher. Jesus has come to call us back to God, and part of that includes teaching. Sometimes we can get caught up in focusing too much on the signs that Jesus performs to the detriment of not paying attention to his teaching. Yet, it is through his teaching that Jesus answers the questions that arise after witnessing his great works. In today's Gospel reading, Jesus wants to teach by inviting his listeners to a deeper reflection (even his own apostles got to understand the teaching only with some help). At first glance, Jesus' teachings always appear to us as if directed to a particular audience. We always fail to see ourselves as part of the intended recipients. Maybe this is what happened to the apostles. And this can be true of us today, and especially with today's reading. 
We have often interpreted the parable of the sower by categorizing and identifying ourselves as belonging to a particular type of soil. While certainly this is what is reported as the interpretation, a deeper reflection will lead us to a broader understanding of the parable, an understanding that is more inclusive and non-judgmental. The scriptural interpretation identifies our receptivity to the word of God as the soil, and rightly so. The word of God is directed at us so that we can cooperate with God and yield the desired fruits. There are times when we totally cooperate with the word of God, and there are times that we fail to totally cooperate with God's word. There are those times that we yield a hundred-fold, but there are also times when we yield a mere thirty-fold. Just as the same piece of land will produce different yields depending on how well the land is prepared, so do we. At one time I will be a rocky soil, at another a perfectly good soil. It takes me to recognize what type of soil I am at any particular point and adjust appropriately. I am the soil. I am the different types of soil.