What happened when two gentlemen from Goa came to see Sai Baba, and why was his request for Dakshina so unusual?

In Chapter 36 of the Shri Sai Satcharitra, two gentlemen from Goa arrived for Sai Baba's darshan. A peculiar event occurred regarding their offerings, or Dakshina. Sai Baba specifically asked one of the men for fifteen rupees, which the man gave with joy. However, when the second gentleman voluntarily offered thirty-five rupees, Sai Baba immediately rejected the offering. This apparent partiality surprised everyone present, including Madhavrao (Shama), who questioned Baba about it. Baba's initial explanation was cryptic, stating, "I don't take anything from anyone. Mother Masjid demands what is owed, and the giver becomes free from debt." This incident, detailed in Chapter 36, serves as a prelude to a deeper teaching on karmic debts.