Ravana sentenced Hanuman to death , after being enraged by his words. Immediately Vibhishana, Ravanas younger brother intervened. Its unfair to give death sentence to a messenger who came here to express what he has been asked to by Rama. However , Vibhishana kept thinking about how to convince Ravana.
Vibhishana told Ravana, that its not an act of dignity for him to Sentence the messenger to death. Though everyone realizes that this is a very evil Vanara, it might not bring good fame for you if you sentence it to death. The future will speak about how you have killed a Vanara messenger and not about all the evil things that it did.
Ravana was furious and he said, there is nothing wrong in killing an enemy who has done damage.
Vibheeshana replied, “ The King of Lanka! At no point in history, a messenger is killed. There is no doubt that he is most dangerous and evil. But there are alternatives to killing him. We can resort to shaving his head, dotting him with black marks, beating etc. The actual people who has to be punished is the one who sent this Vanara. You have to punish Rama and Lakshmana and not this vanara. Please start making arrangements for that”
Sensing justice in what Vibheeshana said, Ravana calmed down and started to think what could be the punishment for this Vanara.