How did Sai Baba manage to light the lamps in the mosque when the shopkeepers refused to give him any more oil?

When the grocers conspired to stop the 'nuisance' of giving free oil and refused his request, Sai Baba performed an incredible miracle. According to Chapter 5, he returned to the mosque, took his tin pot which contained a tiny bit of oil, and poured water into it. He then drank this mixture as an offering to Brahman. Afterwards, he took plain water, poured it into the lamps, and lit the wicks. To the amazement of the watching grocers, the lamps filled with water burned brightly all night long, demonstrating Baba's divine power.