"The food that is required for sustaining the body is conducive to health only when it is consumed within limits. Over-eating poisons the physical system. Food may give satisfaction or cause illness. By his food habits man is becoming a prey to disease. Food is essential, but it must be taken within limit for it to be wholesome. Likewise wealth is essential but within limits. When there is excessive wealth, many dangers ensue. With excessive wealth man turns arrogant and loses the sense of discrimination between right and wrong. He becomes a Duryodhana who exemplified greed rather than a Karna who was noted for his generosity." 

-Sathya Sai Baba, “The Avatar and the devotees” Discourse 23 November 1994
http://www.sssbpt.info/ssspeaks/volume27/sss27-31.pdf

"Work done, with no concern or desire for profit, purely out of love or from a sense of duty, is yoga. Such yoga destroys one’s animal nature and transforms one into a divine being. Serving others, visualising them as kindred Atmas, will help one to progress; it will save one from sliding down from the spiritual stage attained. Selfless service (seva) is far more salutary than even vows and worship (puja). Service disintegrates the selfishness latent in you; it opens the heart wide; it makes the heart blossom."

-Sathya Sai Baba, “Loving Service” Vidya Vahini, Chapter 8
http://www.sssbpt.info/vahinis/Vidya/Vidya08.pdf