Jesus’ message to his followers is “The Kingdom is coming soon,” within your lifetime, and you need to repent for God’s final judgment.  It is unlikely later writers would put this on Jesus’ lips since it is false.  Jesus taught to get into this kingdom you had to behave in a certain way, and much of Jesus’ teaching is how to behave.  Jesus had a distinctive understanding of what the Torah was saying about how to behave to one another: You must love your neighbor as yourself, but this was to be extended beyond your family, friends, and community to anyone in need, including you enemies.  This is not about whether you like someone, but how you treat them.  Do that, and you will enter into the Kingdom.  The story of the sheep and goats argues that regardless of who you are or what you believe, if you did not take care of those in need you will be destroyed.  Those who took care of those in need are brought into paradise.  This is where the idea of helping others that have no relation to us in the west comes from: providing disaster relief; feeding the hungry; etc. 

Again, though, I would stress there is nothing ethical about being moral to get a reward.  The donkey doesn’t labor because it has a protestant work ethic.  It is trying to get the carrot you are dangling in front of him.  Indeed, reward is conspicuous here, since why would someone help if not to be rewarded by at least a warm fuzzy feeling, or the sense of a job well done?