It's all about the authority of Jesus in this episode. It's shown in stories involving demons, pigs, forgiveness of sins and baptism. There is a lot to cover in these texts.
A single, fifteen minute sermon that proclaims Christ and him crucified for you is more important than hundreds of hours of lectures by experts on revitalizing your ministry.
The arrangement was made with Abraham when God claimed for Himself all of his being, and put the seal of His promise upon the most personal member of his anatomy.