What's the story behind Sai Baba lighting lamps with water?

According to the narrative in Chapter 5, Sai Baba demonstrated a remarkable miracle after local shopkeepers refused to give him oil for his lamps. The grocers, tired of providing free oil daily, had conspired to deny him. In response, Baba returned to the mosque, took his tin pot which had a minuscule amount of oil, poured water into it, and drank it as an offering. He then filled the lamps with plain water and lit the wicks. To the amazement of the watching grocers, the lamps burned brightly all night long using only water. This event, as described in Chapter 5, showcased his divine power and caused the shopkeepers to feel deep repentance for their actions.