Mencius - Book 5, Part 2, Chapter 6B

Chang pursued, 'Why is it that the scholar will thus accept the prince's help, but will not accept his pay?' The answer was, 'He does not presume to do so.' 'I venture to ask why he does not presume to do so.' 'Even the keepers of the gates, with their watchmen's sticks, have their regular offices for which they can take their support from the prince. He who without a regular office should receive the pay of the prince must be deemed disrespectful.'

Chang asked, 'If the prince sends a scholar a present, he accepts it; I do not know whether this present may be constantly repeated.' Mencius answered, 'There was the conduct of the duke Mû to Tsze-sze He made frequent inquiries after Tsze-sze's health, and sent him frequent presents of cooked meat. Tsze-sze was displeased; and at length, having motioned to the messenger to go outside the great door, he bowed his head to the ground with his face to the north, did obeisance twice, and declined the gift, saying, "From this time forth I shall know that the prince supports me as a dog or a horse." And so from that time a servant was no more sent with the presents. When a prince professes to be pleased with a man of talents and virtue, and can neither promote him to office, nor support him in the proper way, can he be said to be pleased with him?

~ James Legge translation via nothingistic.org ~

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