How did the incident with the sugary tea demonstrate Sai Baba's omniscience to Cholkar?

The incident with the sugary tea was a powerful and personal demonstration of Sai Baba's omniscience. After Cholkar had fulfilled his vow, he was with another devotee named Jog. As described in Chapter 15, Baba specifically instructed Jog: "Give him cups of tea, well-filled with sugar." This was profoundly significant because Baba did not drink tea, and more importantly, Cholkar had been secretly abstaining from sugar as a penance for delaying his vow. This command revealed that Baba was aware of Cholkar's private sacrifice. As Chapter 15 notes, this was the "full hint" that proved Baba knew the details of the vow, the hardship causing the delay, and the secret renunciation of sugar, thereby confirming Cholkar's faith in an unforgettable way.