Can you provide a summary of the events and teachings described in Chapter 20 of the Sai Satcharitra?

Chapter 20 opens with salutations and describes a vivid scene at Shirdi after the noon Aarti. It portrays Sai Baba lovingly distributing Udi to his devotees, applying it to their foreheads, and then sending them off to have their meals. The narrative, as detailed in this chapter, then transitions to the story of Das Ganu, who was writing a Marathi commentary on the Ishavasya Upanishad. When Das Ganu struggled to understand the text's deep, internal meaning, he sought guidance from Sai Baba. Baba promised that the doubt would be resolved by a maidservant at Kaka’s house. The chapter concludes by emphasizing that understanding profound scriptures is impossible without a Guru's grace, as the hidden truth only reveals itself to the humble and devoted.