The central aspect of the teaching of Jesus was that concerning the Kingdom of God. Of this there can be no doubt. . . .Jesus appeared as one who proclaimed the Kingdom; all else in his message and ministry serves a function in relation to that proclamation and derives its meaning from it. The challenge to discipleship, the ethical teaching, the disputes about oral tradition or ceremonial law, even the pronouncement of forgiveness of sins and the welcoming of the outcast in the name of Godall these are to be understood in the context of the Kingdom proclamation or they are not to be understood at all.
Norman Perrin, Rediscovering the Teaching of Jesus, pg. 54.