Consider Matthew's Sermon on the Mount and Luke's Sermon on the Plain. What was the purpose of these sermons? It would seem the focus is on those people who had already decided to follow Jesus. He was giving them a way of life that he expected them to follow. Guidelines for Kingdom living. For example, Jesus emphasized a type of forgiveness which went beyond the Jewish understanding of forgiveness. If a person speaks ill of you, shake it off. If someone slaps your face, turn your face to receive the second slap. However, you need to understand the reason for your actions. It was because God is kind to the ungrateful and the wicked. Be merciful just as your father is merciful (Luke 6:35-36).
It seems the goal of these sermons was to develop a Christian lifestyle which is gracious and generous to others. Forgive, and you will be forgiven; give and it will be given to you (Luke 6:37-38).