How did Sai Baba demonstrate his omniscience regarding Cholkar's secret vow, and what was the intended effect of this revelation?

Sai Baba demonstrated his all-knowing nature in a subtle yet profound manner. After Cholkar had fulfilled his vow and was a guest of Jog, Baba instructed Jog to give Cholkar 'cups of tea, well-filled with sugar.' As Chapter 15 recounts, these words fell on Cholkar's ears and left him amazed, as only he knew about his secret vow to abstain from sugar. The intended effect was to provide a full hint that his vow and the penance for the delay were accepted. This personal experience was meant to confirm Cholkar's faith and impress the 'stamp of devotion' upon him, proving that Baba was aware of everything, even his most private thoughts and actions.