Our willingness (or ability) to hear God's word is directly correlated to the condition of our heart. If our heart is the soil in this parable, we need to evaluate the condition of our soil, so-to-speak. If it's not fertile, if it's not receptive, if it's full of thorns, we will go through life missing the full truth. Jesus himself is the Way, the Truth, and the Life (Jn 14:6) and we know that in the beginning was the Word (Jn 1:1). A major component of our walk with Christ is to be prepping the soil, so that his truth – the truth of who Jesus is, will be able to take root, by the work of the Holy Spirit, for the glory of God.