One of the great things about Jesus' teachings is that at the heart of it are two commands "You shall love the Lord your God with all your heart and with all your soul and with all your mind." and "You shall love your neighbor as yourself.", the two commands upon which he says "depend all the Law and the Prophets." He even tells one man that this is all you need to do in order to "inherit eternal life", after which he confounds everyone's idea of who their neighbors are. Now, we can probably all agree that what it means to obey these two commands is an incredibly nuanced and complicated affair. How do you love God with everything you have, so that you have no other principalities, powers, objects, people, loyalties, loves or anything else commanding your actions? How do you love people as much as you, a selfish creature, love yourself? I think he keeps his statements simple because you can not write out laws to wholly entail love for all people. You can not sum right living up in a set of rules, for right living is loving.