What was the purpose behind Sai Baba's fondness for lighting lamps, and how did he react when the shopkeepers denied him oil?

According to Chapter 0, Sai Baba's practice of lighting many lamps in the Masjid and temples was not to satisfy a personal whim, but rather had a benevolent motive: doing good for the people. He would go to the houses of oil-men and grocers to procure oil for these lamps. When they eventually refused to give him any more, his routine was not disrupted. In a display of his divine power, Maharaj simply put water in the lamps instead of oil and lit them as usual. The lamps burned all night, proving that his actions were not dependent on worldly provisions and amazing the very people who had denied him.