Hanuman is widely revered for his immense devotion and love for Lord Rama and Mata Sita. He ideally defines ‘Dasyabhava’ devotion, which is known for the union of love between the master and servant. One such incident clearly defines the love of Hanuman for his master.
When Lord Rama and Sita ji came back from Sri Lanka after winning over Ravana, lord Rama decided to conduct a grand ceremony. In the celebration he awarded all his well wishers for supporting and showering their love. When Hanuman ji went to Rama for his reward, he immediately hugged him and said that he can never pay for the humble service and devotion of Hanuman. But Mata Sita requested Rama to give something to Hanuman apart from the honour, thus Lord Rama offered him and Sita ji offered him a precious stoned necklace.
As soon as Hanuman took the necklace in his hands, he began to tear it apart and peers into each stone. Everybody was shocked to see the activity of Hanuman and started asking him the reason for breaking the precious gift. Hanuman ji answered that he was looking in each stone to check the presence of lord Rama and Sita ji. If something does not have the presence of his master then it is a waste for him.
To prove the depth of his love for Rama and Sita, Hanuman tears his chest open and everyone could actually see the image of of Rama and Sita in his heart.