Mencius - Book 5, Part 2, Chapter 4A

Wan Chang asked Mencius, saying, 'I venture to ask what feeling of the mind is expressed in the presents of friendship?' Mencius replied, 'The feeling of respect.'

'How is it,' pursued Chang, 'that the declining a present is accounted disrespectful?' The answer was, 'When one of honorable rank presents a gift, to say in the mind, "Was the way in which he got this righteous or not? I must know this before I can receive it;" this is deemed disrespectful, and therefore presents are not declined.'

Wan Chang asked again, 'When one does not take on him in so many express words to refuse the gift, but having declined it in his heart, saying, "It was taken by him unrighteously from the people," and then assigns some other reason for not receiving it; is not this a proper course?' Mencius said, 'When the donor offers it on a ground of reason, and his manner of doing so is according to propriety; in such a case Confucius would have received it.'
~ James Legge translation via nothingistic.org ~

Go here to read the introductory post to this serialized version of the Works of Mencius.