What were the shopkeepers' motivations for denying Baba oil, and how did they react when they saw the lamps burning on water?

The source material in Chapter 5 explains that the grocers who had been providing oil for free developed a 'wicked idea' and conspired to stop what they had come to see as a 'nuisance.' When Baba came for oil as usual, they all refused him. After they witnessed him light the lamps with water, which then burned all night, they were completely amazed, described as putting their fingers in their mouths. They immediately felt repentance, realizing they had sinned by lying to Baba and causing him needless trouble, and they began to tremble at the display of his power.