A parable is an illustration or short story by which can be drawn a single truth or answer to a single question. Jesus used parables as a means of teaching the message of the kingdom in a way that listeners would understand better than by just preaching. For example, Jesus could have just said, ‘love your neighbor as yourself,’ and when asked ‘who is my neighbor?’ Jesus could have replied with a statement or a lecture. But the point would not have been as clear or as sharp as the story of the Good Samaritan. In addition, when he told the story of The Prodigal Son, the point of God’s grace and forgiveness for the lost; and all of heaven rejoicing for the lost sinner becomes so much more poignant.
The reasons for storytelling are not only so the point can come across more clearly, but also so the people could remember them better, including his disciples, who would have told them later on after Jesus’ resurrection and would have passed them down to a new set of disciples, and so on. The stories also lend themselves to further study and reflection whereas a flat out dialogue might not.