How did Sai Baba prove his omniscience to his devotee Cholkar?

Sai Baba demonstrated his omniscience to Cholkar in a very personal and astonishing way. As recounted in Chapter 15, Cholkar had secretly given up sugar as a personal penance because he was delayed in fulfilling his vow to Baba. After he finally arrived in Shirdi, had darshan, and fulfilled his vow, he was a guest at Mr. Jog's place. Just as he was leaving, Baba instructed Jog, 'Give him cups of tea, well-filled with sugar.' This instruction was profound because Baba himself did not drink tea, and it directly addressed Cholkar's secret sacrifice, which no one else knew about. This act confirmed for Cholkar that Baba was aware of his innermost thoughts and actions, solidifying his faith.