忘恩负义

有子曰：“信近于义，言可复也。恭近于礼，远耻辱也。因不失其亲，亦可宗也。”

The first principle means that to keep a promise or invitation, the promise or invitation has to stick to your integrity and be a promise worth keeping. The second principle means to only show respect to those who deserve it. Those who try to murder you or harm you do not deserve your respect. The final principle means that if the people you rely on and respect are worth your relying on and respect, then you are also worthy of respect.In the story, these principles were shown. The first principle was shown when one of the friends said that he would go to 魏 country first and secure a position, and then invite the other over. If the second friend had used the first principle, he would have discovered that the first friend actually wanted to hurt him, and that he probably should not follow to 魏 country. The second principle was shown when the first friend was really disrespectful to the second friend when he came, just because the emperor praised the second friend a bit. Then he tried to murder the second friend, and the second friend found out and stopped trusting and respecting the first friend. The relationship dissolved and the second friend ended up killing the first friend.