Dobby saw the reactions on their faces and he realized that the other two men must be like the Captain in the sense that they didn't have much knowledge of magic. Dobby knew that it was probably best that he explained a little more, so that they wouldn't be upset with him. He was about to do just that when the Captain thanked him, and that brought a huge smile to Dobby's face. "Dobby is glad you are happy, sir" he answered and then he turned to the other two men. "That is Dobby's magic, sirs. Dobby will use his magic to serve and protect the captain" was his explanation.