We are stewards of the light of the Gospel, and we are called to build God's Kingdom by sharing it. Jesus shares three parables to further our understanding of His Kingdom.
In the parable of the sower, the seed and the soil, Jesus teaches that the condition of the human (spiritual) heart determines how we receive the Gospel.
Jesus' primary mission was to bring the greatest healing of all - atonement or the sins of mankind. He never promised to heal everyone of their temporal illnesses and injuries, although He did heal some to authenticate the words that He spoke.