Note the words ‘retain’ (NIV) or ‘take it to themselves’(NJB). We can hear the word but not necessarily retain it as the parable has explained because ‘we have not taken it to ourselves’.  The only way we are going to bear fruit in our lives is if we recognise that God’s loving and challenging Word is addressed to us personally. It is He who then makes the plant grow and bear fruit. Indeed, by living in the Spirit, we begin to see that ‘the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control  (Gal. 5:22).