How did Sai Baba prove his omniscience to Cholkar?

Sai Baba demonstrated his all-knowing nature in a subtle yet powerful way. As Chapter 15 recounts, after Cholkar had fulfilled his vow and was with another devotee named Jog, Baba specifically instructed Jog, 'Give him cups of tea, well-filled with sugar.' This command was profoundly meaningful because Cholkar had secretly given up sugar as penance. Baba did not even drink tea, so the instruction was clearly a direct message to Cholkar, confirming that his private vow and personal sacrifice were fully known to Baba, which brought tears of joy to Cholkar's eyes.