I recently read an article about the Hard Teachings of Jesus. They are called "hard teachings" because most people find them very demanding and difficult to follow. In fact many people either ignore them or try to find ways to alter their meaning so as to convert them into less demanding forms.
Perhaps the best-known hard teaching is the instruction to "turn the other cheek" (Matthew 5:39). Members of a few small groups such as the Quakers are taught to strictly follow this by refusing to fight back even if someone attacks them. But many Christians view it as some kind of anomaly which shouldn't be taken literally. Some people even argue that Jesus wasn't talking about a situation in which someone hits you, even though in the same verse he says "do not resist an evil person."
Another component of Jesus' teaching that causes problems for many Christians was his strong disapproval of attempts to acquire money and wealth. The article cites several of his statements that express this disapproval, such as "woe to you who are rich" (Luke 6:24) and "do not store up for yourselves treasures on earth" (Matthew 6:19). But many people believe that disapproval isn't condemnation, and that wealthy individuals still have a realistic chance to go to heaven after they die if they use their money for good purposes.
The article says that teachings such as these have led some people to regard Jesus as a social reformer or even a communist. But it argues that they actually sprang from his great compassion and willingness to forgive.
To read the complete article, go to Hard Teachings of Jesus. It contains several other examples of his hard teachings in addition those I mentioned here.